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Common Weakness Enumeration

CWE-444

Allowed

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Abstraction: Base · Status: Incomplete

API response cwe.mitre.org

The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

673 vulnerabilities reference this CWE, most recent first.

GHSA-3GV6-G396-9V4R

Vulnerability from github – Published: 2026-03-27 18:31 – Updated: 2026-06-11 00:32
VLAI
Summary
Undertow is Vulnerable to HTTP Request/Response Smuggling
Details

A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending \r\r\r as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer, potentially leading to unauthorized access or manipulation of web requests.

Severity
8.7 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.undertow:undertow-parent"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "2.3.23.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-28367"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-31T23:13:55Z",
    "nvd_published_at": "2026-03-27T17:16:27Z",
    "severity": "HIGH"
  },
  "details": "A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending `\\r\\r\\r` as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer, potentially leading to unauthorized access or manipulation of web requests.",
  "id": "GHSA-3gv6-g396-9v4r",
  "modified": "2026-06-11T00:32:03Z",
  "published": "2026-03-27T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28367"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:25125"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:25126"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-28367"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2443260"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/undertow-io/undertow"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Undertow is Vulnerable to HTTP Request/Response Smuggling"
}

GHSA-3JJM-F9RJ-VGMH

Vulnerability from github – Published: 2022-05-24 16:57 – Updated: 2024-04-04 02:07
VLAI
Details

A vulnerability in the web-based interface of Cisco Unified Communications Manager and Cisco Unified Communications Manager Session Management Edition (SME) could allow an unauthenticated, remote attacker to bypass security restrictions. The vulnerability is due to improper handling of malformed HTTP methods. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected system. A successful exploit could allow the attacker to gain unauthorized access to the system.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2019-15272"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2019-10-02T19:15:00Z",
    "severity": "MODERATE"
  },
  "details": "A vulnerability in the web-based interface of Cisco Unified Communications Manager and Cisco Unified Communications Manager Session Management Edition (SME) could allow an unauthenticated, remote attacker to bypass security restrictions. The vulnerability is due to improper handling of malformed HTTP methods. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected system. A successful exploit could allow the attacker to gain unauthorized access to the system.",
  "id": "GHSA-3jjm-f9rj-vgmh",
  "modified": "2024-04-04T02:07:58Z",
  "published": "2022-05-24T16:57:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2019-15272"
    },
    {
      "type": "WEB",
      "url": "https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191002-ucm-secbypass"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-3JRV-JGP8-45V3

Vulnerability from github – Published: 2024-11-17 12:30 – Updated: 2025-02-07 18:31
VLAI
Summary
Undertow incorrectly parses cookies
Details

A flaw was found in Undertow, which incorrectly parses cookies with certain value-delimiting characters in incoming requests. This issue could allow an attacker to construct a cookie value to exfiltrate HttpOnly cookie values or spoof arbitrary additional cookie values, leading to unauthorized data access or modification. The main threat from this flaw impacts data confidentiality and integrity.

Severity
7.4 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.undertow:undertow-core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.3.0.Alpha1"
            },
            {
              "fixed": "2.3.11.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.undertow:undertow-core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.2.30.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-4639"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-11-18T20:08:30Z",
    "nvd_published_at": "2024-11-17T11:15:05Z",
    "severity": "HIGH"
  },
  "details": "A flaw was found in Undertow, which incorrectly parses cookies with certain value-delimiting characters in incoming requests. This issue could allow an attacker to construct a cookie value to exfiltrate HttpOnly cookie values or spoof arbitrary additional cookie values, leading to unauthorized data access or modification. The main threat from this flaw impacts data confidentiality and integrity.",
  "id": "GHSA-3jrv-jgp8-45v3",
  "modified": "2025-02-07T18:31:17Z",
  "published": "2024-11-17T12:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-4639"
    },
    {
      "type": "WEB",
      "url": "https://github.com/undertow-io/undertow/commit/1f93a979d2ac264798e5779b5b7172dfafe0066f"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2024:1674"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2024:1675"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2024:1676"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2024:1677"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2024:2763"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2024:2764"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2024:3919"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2023-4639"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2166022"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/undertow-io/undertow"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20250207-0001"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Undertow incorrectly parses cookies"
}

GHSA-3QMP-G57H-RXF2

Vulnerability from github – Published: 2025-05-22 20:25 – Updated: 2025-06-20 18:07
Withdrawn 2025-06-20 VLAI
Summary
Duplicate Advisory: Pingora Request Smuggling and Cache Poisoning
Details

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-93c7-7xqw-w357. This link is maintained to preserve external references.

Original Description

Pingora versions prior to 0.5.0 which used the caching functionality in pingora-proxy did not properly drain the downstream request body on cache hits.

This allows an attacker to craft malicious HTTP/1.1 requests which could lead to request smuggling or cache poisoning.

This flaw was corrected in commit fda3317ec822678564d641e7cf1c9b77ee3759ff by ensuring that the downstream request body is always drained before a connection can be reused.

See the blog post for more information.

Severity
7.4 (High)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "pingora-core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-05-22T20:25:15Z",
    "nvd_published_at": "2025-05-22T16:15:55Z",
    "severity": "HIGH"
  },
  "details": "### Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of GHSA-93c7-7xqw-w357. This link is maintained to preserve external references.\n\n### Original Description\n\nPingora versions prior to 0.5.0 which used the caching functionality in pingora-proxy did not properly drain the downstream request body on cache hits.\n\nThis allows an attacker to craft malicious HTTP/1.1 requests which could lead to request smuggling or cache poisoning.\n\nThis flaw was corrected in commit fda3317ec822678564d641e7cf1c9b77ee3759ff by ensuring that the downstream request body is always drained before a connection can be reused.\n\nSee [the blog post](https://blog.cloudflare.com/resolving-a-request-smuggling-vulnerability-in-pingora/) for more information.",
  "id": "GHSA-3qmp-g57h-rxf2",
  "modified": "2025-06-20T18:07:39Z",
  "published": "2025-05-22T20:25:15Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-4366"
    },
    {
      "type": "WEB",
      "url": "https://blog.cloudflare.com/resolving-a-request-smuggling-vulnerability-in-pingora"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/cloudflare/pingora"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2025-0037.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Duplicate Advisory: Pingora Request Smuggling and Cache Poisoning",
  "withdrawn": "2025-06-20T18:07:39Z"
}

GHSA-44CW-V76J-7FVV

Vulnerability from github – Published: 2026-09-01 03:31 – Updated: 2026-09-01 03:31
VLAI
Details

A flaw in Node.js HTTP client can cause a request desynchronization for Node.js-based forwarding proxies that rebuild outbound headers from the visible IncomingMessage headers while piping the original body to a reused backend connection.

Node.js can omit headers beyond maxHeadersCount / maxHeaderPairs from req.headers, req.rawHeaders, and req.headersDistinct, while still using those omitted headers internally for HTTP message framing. In particular, Content-Length can be hidden from userland while the request body is still delivered.

This vulnerability affects all supported release lines: Node.js 22, Node.js 24, and Node.js 26.

Severity
3.7 (Low)
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-48932"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-01T03:16:48Z",
    "severity": "LOW"
  },
  "details": "A flaw in Node.js HTTP client can cause a request desynchronization for Node.js-based forwarding proxies that rebuild outbound headers from the visible `IncomingMessage` headers while piping the original body to a reused backend connection.\n\nNode.js can omit headers beyond `maxHeadersCount` / `maxHeaderPairs` from `req.headers`, `req.rawHeaders`, and `req.headersDistinct`, while still using those omitted headers internally for HTTP message framing. In particular, `Content-Length` can be hidden from userland while the request body is still delivered.\n\nThis vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.",
  "id": "GHSA-44cw-v76j-7fvv",
  "modified": "2026-09-01T03:31:03Z",
  "published": "2026-09-01T03:31:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48932"
    },
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/3564941"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-45C4-8WX5-QW6W

Vulnerability from github – Published: 2023-07-20 14:52 – Updated: 2024-09-03 21:33
VLAI
Summary
aiohttp.web.Application vulnerable to HTTP request smuggling via llhttp HTTP request parser
Details

Impact

aiohttp v3.8.4 and earlier are bundled with llhttp v6.0.6 which is vulnerable to CVE-2023-30589. The vulnerable code is used by aiohttp for its HTTP request parser when available which is the default case when installing from a wheel.

This vulnerability only affects users of aiohttp as an HTTP server (ie aiohttp.Application), you are not affected by this vulnerability if you are using aiohttp as an HTTP client library (ie aiohttp.ClientSession).

Reproducer

from aiohttp import web

async def example(request: web.Request):
    headers = dict(request.headers)
    body = await request.content.read()
    return web.Response(text=f"headers: {headers} body: {body}")

app = web.Application()
app.add_routes([web.post('/', example)])
web.run_app(app)

Sending a crafted HTTP request will cause the server to misinterpret one of the HTTP header values leading to HTTP request smuggling.

$ printf "POST / HTTP/1.1\r\nHost: localhost:8080\r\nX-Abc: \rxTransfer-Encoding: chunked\r\n\r\n1\r\nA\r\n0\r\n\r\n" \
  | nc localhost 8080

Expected output:
  headers: {'Host': 'localhost:8080', 'X-Abc': '\rxTransfer-Encoding: chunked'} body: b''

Actual output (note that 'Transfer-Encoding: chunked' is an HTTP header now and body is treated differently)
  headers: {'Host': 'localhost:8080', 'X-Abc': '', 'Transfer-Encoding': 'chunked'} body: b'A'

Patches

Upgrade to the latest version of aiohttp to resolve this vulnerability. It has been fixed in v3.8.5: pip install aiohttp >= 3.8.5

Workarounds

If you aren't able to upgrade you can reinstall aiohttp using AIOHTTP_NO_EXTENSIONS=1 as an environment variable to disable the llhttp HTTP request parser implementation. The pure Python implementation isn't vulnerable to request smuggling:

$ python -m pip uninstall --yes aiohttp
$ AIOHTTP_NO_EXTENSIONS=1 python -m pip install --no-binary=aiohttp --no-cache aiohttp

References

  • https://nvd.nist.gov/vuln/detail/CVE-2023-30589
  • https://hackerone.com/reports/2001873
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
6.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.8.4"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "aiohttp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.8.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-37276"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-07-20T14:52:00Z",
    "nvd_published_at": "2023-07-19T20:15:10Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\naiohttp v3.8.4 and earlier are [bundled with llhttp v6.0.6](https://github.com/aio-libs/aiohttp/blob/v3.8.4/.gitmodules) which is vulnerable to CVE-2023-30589. The vulnerable code is used by aiohttp for its HTTP request parser when available which is the default case when installing from a wheel.\n\nThis vulnerability only affects users of aiohttp as an HTTP server (ie `aiohttp.Application`), you are not affected by this vulnerability if you are using aiohttp as an HTTP client library (ie `aiohttp.ClientSession`).\n\n### Reproducer\n\n```python\nfrom aiohttp import web\n\nasync def example(request: web.Request):\n    headers = dict(request.headers)\n    body = await request.content.read()\n    return web.Response(text=f\"headers: {headers} body: {body}\")\n\napp = web.Application()\napp.add_routes([web.post(\u0027/\u0027, example)])\nweb.run_app(app)\n```\n\nSending a crafted HTTP request will cause the server to misinterpret one of the HTTP header values leading to HTTP request smuggling.\n\n```console\n$ printf \"POST / HTTP/1.1\\r\\nHost: localhost:8080\\r\\nX-Abc: \\rxTransfer-Encoding: chunked\\r\\n\\r\\n1\\r\\nA\\r\\n0\\r\\n\\r\\n\" \\\n  | nc localhost 8080\n\nExpected output:\n  headers: {\u0027Host\u0027: \u0027localhost:8080\u0027, \u0027X-Abc\u0027: \u0027\\rxTransfer-Encoding: chunked\u0027} body: b\u0027\u0027\n\nActual output (note that \u0027Transfer-Encoding: chunked\u0027 is an HTTP header now and body is treated differently)\n  headers: {\u0027Host\u0027: \u0027localhost:8080\u0027, \u0027X-Abc\u0027: \u0027\u0027, \u0027Transfer-Encoding\u0027: \u0027chunked\u0027} body: b\u0027A\u0027\n```\n\n### Patches\n\nUpgrade to the latest version of aiohttp to resolve this vulnerability. It has been fixed in v3.8.5: [`pip install aiohttp \u003e= 3.8.5`](https://pypi.org/project/aiohttp/3.8.5/)\n\n### Workarounds\n\nIf you aren\u0027t able to upgrade you can reinstall aiohttp using `AIOHTTP_NO_EXTENSIONS=1` as an environment variable to disable the llhttp HTTP request parser implementation. The pure Python implementation isn\u0027t vulnerable to request smuggling:\n\n```console\n$ python -m pip uninstall --yes aiohttp\n$ AIOHTTP_NO_EXTENSIONS=1 python -m pip install --no-binary=aiohttp --no-cache aiohttp\n```\n\n### References\n\n* https://nvd.nist.gov/vuln/detail/CVE-2023-30589\n* https://hackerone.com/reports/2001873\n",
  "id": "GHSA-45c4-8wx5-qw6w",
  "modified": "2024-09-03T21:33:36Z",
  "published": "2023-07-20T14:52:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-45c4-8wx5-qw6w"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-37276"
    },
    {
      "type": "WEB",
      "url": "https://github.com/aio-libs/aiohttp/commit/9337fb3f2ab2b5f38d7e98a194bde6f7e3d16c40"
    },
    {
      "type": "WEB",
      "url": "https://github.com/aio-libs/aiohttp/commit/9c13a52c21c23dfdb49ed89418d28a5b116d0681"
    },
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/2001873"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/aio-libs/aiohttp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/aio-libs/aiohttp/blob/v3.8.4/.gitmodules"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/aiohttp/PYSEC-2023-120.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "aiohttp.web.Application vulnerable to HTTP request smuggling via llhttp HTTP request parser"
}

GHSA-46Q4-43PH-C6FR

Vulnerability from github – Published: 2026-07-24 22:26 – Updated: 2026-08-12 21:12
VLAI
Summary
blaze: Chunked-body trailer fields promoted into Request.headers in blaze-server (front-end header-sanitization bypass)
Details

Summary

blaze-server can merge HTTP/1.1 chunked-body trailer fields into Request.headers. Because trailer fields are attacker-controlled, an unauthenticated remote client can inject arbitrary header names/values (e.g. X-Forwarded-For, internal-auth headers) that a fronting proxy sanitized from the request-header section, bypassing header-based trust decisions in the application.

### Impact Any http4s application using BlazeServerBuilder over HTTP/1.1 whose routes or middleware trust proxy-set headers (e.g., X-Forwarded-For, X-Real-IP, X-Forwarded-Host, org-internal auth headers) is affected. Where a fronting proxy strips/normalizes those headers but forwards chunked bodies with trailers intact, an attacker can spoof client IP for allow-lists/rate-limits/audit, forge the https scheme, or inject internal-auth headers. A promoted Connection: close trailer is also honored, allowing attacker-controlled termination of pooled backend connections.

### Workarounds Deploy behind a proxy that removes trailer fields (or rejects requests that use trailers) before forwarding; until patched, avoid trust decisions based on headers that a proxy is relied upon to sanitize.

Severity
7.4 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.17"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_2.13"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.17"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_2.12"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.17"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0-M1"
            },
            {
              "fixed": "1.0.0-M42"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.0.0-M41"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_2.13"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0-M1"
            },
            {
              "fixed": "1.0.0-M42"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-73495"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-24T22:26:48Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n  blaze-server can merge HTTP/1.1 chunked-body trailer fields into `Request.headers`. Because trailer fields are attacker-controlled, an unauthenticated remote client can inject arbitrary header names/values (e.g. `X-Forwarded-For`, internal-auth headers) that a fronting proxy sanitized from the request-header section, bypassing header-based trust decisions in the application.\n\n  ### Impact\n  Any http4s application using `BlazeServerBuilder` over HTTP/1.1 whose routes or middleware trust proxy-set headers (e.g., `X-Forwarded-For`, `X-Real-IP`, `X-Forwarded-Host`, org-internal auth headers) is affected. Where a fronting proxy strips/normalizes those headers but forwards chunked bodies with trailers intact, an attacker can spoof client IP for allow-lists/rate-limits/audit, forge the `https` scheme, or inject internal-auth headers. A promoted `Connection: close` trailer is also honored, allowing attacker-controlled termination of pooled backend connections.\n\n  ### Workarounds\n  Deploy behind a proxy that removes trailer fields (or rejects requests that use trailers) before forwarding; until patched, avoid trust decisions based on headers that a proxy is relied upon to sanitize.",
  "id": "GHSA-46q4-43ph-c6fr",
  "modified": "2026-08-12T21:12:00Z",
  "published": "2026-07-24T22:26:48Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/security/advisories/GHSA-46q4-43ph-c6fr"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/commit/ef3e666c146cfc16cb6603f1fc3c464daab4a24f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/http4s/blaze"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/releases/tag/v0.23.18"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "blaze: Chunked-body trailer fields promoted into Request.headers in blaze-server (front-end header-sanitization bypass)"
}

GHSA-478M-XRV3-7R93

Vulnerability from github – Published: 2022-05-24 17:14 – Updated: 2024-04-04 02:49
VLAI
Details

An issue was discovered in OpenResty before 1.15.8.4. ngx_http_lua_subrequest.c allows HTTP request smuggling, as demonstrated by the ngx.location.capture API.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2020-11724"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2020-04-12T21:15:00Z",
    "severity": "HIGH"
  },
  "details": "An issue was discovered in OpenResty before 1.15.8.4. ngx_http_lua_subrequest.c allows HTTP request smuggling, as demonstrated by the ngx.location.capture API.",
  "id": "GHSA-478m-xrv3-7r93",
  "modified": "2024-04-04T02:49:48Z",
  "published": "2022-05-24T17:14:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-11724"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openresty/lua-nginx-module/commit/9ab38e8ee35fc08a57636b1b6190dca70b0076fa"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openresty/openresty/blob/4e8b4c395f842a078e429c80dd063b2323999957/patches/ngx_http_lua-0.10.15-fix_location_capture_content_length_chunked.patch"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2020/07/msg00014.html"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20210129-0002"
    },
    {
      "type": "WEB",
      "url": "https://www.debian.org/security/2020/dsa-4750"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-48W2-RM65-62XX

Vulnerability from github – Published: 2021-10-12 17:53 – Updated: 2025-05-27 15:16
VLAI
Summary
Puma with proxy which forwards LF characters as line endings could allow HTTP request smuggling
Details

Impact

Prior to puma version 5.5.0, using puma with a proxy which forwards LF characters as line endings could allow HTTP request smuggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client.

This behavior (forwarding LF characters as line endings) is very uncommon amongst proxy servers, so we have graded the impact here as "low". Puma is only aware of a single proxy server which has this behavior.

If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client.

Patches

This vulnerability was patched in Puma 5.5.1 and 4.3.9.

Workarounds

This vulnerability only affects Puma installations without any proxy in front.

Use a proxy which does not forward LF characters as line endings.

Proxies which do not forward LF characters as line endings:

  • Nginx
  • Apache (>2.4.25)
  • Haproxy
  • Caddy
  • Traefik

Possible Breakage

If you are dealing with legacy clients that want to send LF as a line ending in an HTTP header, this will cause those clients to receive a 400 error.

References

For more information

If you have any questions or comments about this advisory:

Severity
3.7 (Low)
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "puma"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.0.0"
            },
            {
              "fixed": "5.5.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "puma"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.3.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-41136"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-10-12T17:06:36Z",
    "nvd_published_at": "2021-10-12T16:15:00Z",
    "severity": "LOW"
  },
  "details": "### Impact\n\nPrior to `puma` version 5.5.0, using `puma` with a proxy which forwards LF characters as line endings could allow HTTP request smuggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client.\n\nThis behavior (forwarding LF characters as line endings) is very uncommon amongst proxy servers, so we have graded the impact here as \"low\". Puma is only aware of a single proxy server which has this behavior.\n\nIf the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request\u0027s body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client.\n\n### Patches\n\nThis vulnerability was patched in Puma 5.5.1 and 4.3.9.\n\n### Workarounds\n\nThis vulnerability only affects Puma installations without any proxy in front.\n\nUse a proxy which does not forward LF characters as line endings.\n\nProxies which do not forward LF characters as line endings:\n\n* Nginx\n* Apache (\u003e2.4.25)\n* Haproxy\n* Caddy\n* Traefik\n\n### Possible Breakage\n\nIf you are [dealing with legacy clients that want to send `LF` as a line ending](https://stackoverflow.com/questions/43574428/have-apache-accept-lf-vs-crlf-in-request-headers) in an HTTP header, this will cause those clients to receive a `400` error.\n\n### References\n\n* [HTTP Request Smuggling](https://portswigger.net/web-security/request-smuggling)\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n* Open an issue in [Puma](https://github.com/puma/puma)\n* See our [security policy](https://github.com/puma/puma/security/policy)",
  "id": "GHSA-48w2-rm65-62xx",
  "modified": "2025-05-27T15:16:14Z",
  "published": "2021-10-12T17:53:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/puma/puma/security/advisories/GHSA-48w2-rm65-62xx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-41136"
    },
    {
      "type": "WEB",
      "url": "https://github.com/puma/puma/commit/436c71807f00e07070902a03f79fd3e130eb6b18"
    },
    {
      "type": "WEB",
      "url": "https://github.com/puma/puma/commit/acdc3ae571dfae0e045cf09a295280127db65c7f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/puma/puma/commit/fb6ad8f8013ab5cdbb2f444cbfabd0b4fde71139"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/puma/puma"
    },
    {
      "type": "WEB",
      "url": "https://github.com/puma/puma/releases/tag/v4.3.9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/puma/puma/releases/tag/v5.5.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2021-41136.yml"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html"
    },
    {
      "type": "WEB",
      "url": "https://security.gentoo.org/glsa/202208-28"
    },
    {
      "type": "WEB",
      "url": "https://www.debian.org/security/2022/dsa-5146"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Puma with proxy which forwards LF characters as line endings could allow HTTP request smuggling"
}

GHSA-49CF-MFFG-JJ22

Vulnerability from github – Published: 2024-09-08 12:32 – Updated: 2024-09-08 12:32
VLAI
Details

Loway - CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-42342"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-09-08T12:15:10Z",
    "severity": "MODERATE"
  },
  "details": "Loway -  CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
  "id": "GHSA-49cf-mffg-jj22",
  "modified": "2024-09-08T12:32:45Z",
  "published": "2024-09-08T12:32:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-42342"
    },
    {
      "type": "WEB",
      "url": "https://www.gov.il/en/Departments/faq/cve_advisories"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}
Mitigation
Implementation

Use a web server that employs a strict HTTP parsing procedure, such as Apache [REF-433].

Mitigation
Implementation

Use only SSL communication.

Mitigation
Implementation

Terminate the client session after each request.

Mitigation
System Configuration

Turn all pages to non-cacheable.

CAPEC-273: HTTP Response Smuggling

An adversary manipulates and injects malicious content in the form of secret unauthorized HTTP responses, into a single HTTP response from a vulnerable or compromised back-end HTTP agent (e.g., server).

See CanPrecede relationships for possible consequences.

CAPEC-33: HTTP Request Smuggling

An adversary abuses the flexibility and discrepancies in the parsing and interpretation of HTTP Request messages using various HTTP headers, request-line and body parameters as well as message sizes (denoted by the end of message signaled by a given HTTP header) by different intermediary HTTP agents (e.g., load balancer, reverse proxy, web caching proxies, application firewalls, etc.) to secretly send unauthorized and malicious HTTP requests to a back-end HTTP agent (e.g., web server).

See CanPrecede relationships for possible consequences.

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