Vulnerability-Lookup

CVE-2026-75922 (GCVE-0-2026-75922)

Vulnerability from cvelistv5 – Published: 2026-08-23 18:16 – Updated: 2026-08-23 21:05

Title

Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line

Summary

Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line. PSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, '?' or '#' truncates it the same way. Everything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy's own routing does not expose.

Severity

No CVSS data available.

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests
CWE-93 - Improper Neutralization of CRLF Sequences

Assigner

CPANSec redhat root

References

5 references

URL	Tags
https://metacpan.org/release/LNATION/Reverse-Prox…
https://metacpan.org/release/LNATION/Reverse-Prox…
https://metacpan.org/release/LNATION/Reverse-Prox…
https://metacpan.org/release/LNATION/Reverse-Prox…	release-notes
http://www.openwall.com/lists/oss-security/2026/08/23/2

Impacted products

1 product

Vendor	Product	Version	CPE status
		Affected: 0 , < 0.04 (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
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        "providerMetadata": {
          "dateUpdated": "2026-08-23T21:05:13.636Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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          {
            "url": "http://www.openwall.com/lists/oss-security/2026/08/23/2"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "modules": [
            "Reverse::Proxy"
          ],
          "packageName": "Reverse-Proxy",
          "packageURL": "pkg:cpan/Reverse-Proxy",
          "programFiles": [
            "Proxy.xs"
          ],
          "programRoutines": [
            {
              "name": "rp_target_url"
            },
            {
              "name": "rp_raw_request"
            }
          ],
          "versions": [
            {
              "lessThan": "0.04",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line.\n\nPSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, \u0027?\u0027 or \u0027#\u0027 truncates it the same way.\n\nEverything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy\u0027s own routing does not expose."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-444",
              "description": "CWE-444 Inconsistent Interpretation of HTTP Requests",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-93",
              "description": "CWE-93 Improper Neutralization of CRLF Sequences",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-23T18:16:41.474Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L386-399"
        },
        {
          "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L654-666"
        },
        {
          "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/source/Proxy.xs#L400-426"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/changes"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to Reverse-Proxy 0.04 or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line",
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
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  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-75922",
    "datePublished": "2026-08-23T18:16:41.474Z",
    "dateReserved": "2026-08-18T15:10:32.506Z",
    "dateUpdated": "2026-08-23T21:05:13.636Z",
    "state": "PUBLISHED"
  },
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    "epss": {
      "cve": "CVE-2026-75922",
      "date": "2026-08-24",
      "epss": "0.00262",
      "percentile": "0.17618"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-75922\",\"sourceIdentifier\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"published\":\"2026-08-23T19:16:28.930\",\"lastModified\":\"2026-08-23T21:16:28.150\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line.\\n\\nPSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, \u0027?\u0027 or \u0027#\u0027 truncates it the same way.\\n\\nEverything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy\u0027s own routing does not expose.\"}],\"affected\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"affectedData\":[{\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://cpan.org/modules\",\"packageName\":\"Reverse-Proxy\",\"modules\":[\"Reverse::Proxy\"],\"programFiles\":[\"Proxy.xs\"],\"programRoutines\":[{\"name\":\"rp_target_url\"},{\"name\":\"rp_raw_request\"}],\"packageURL\":\"pkg:cpan/Reverse-Proxy\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"0.04\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{},\"weaknesses\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-93\"},{\"lang\":\"en\",\"value\":\"CWE-444\"}]}],\"references\":[{\"url\":\"https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L386-399\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L654-666\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/changes\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/source/Proxy.xs#L400-426\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/23/2\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}"
  }
}

FKIE_CVE-2026-75922

Vulnerability from fkie_nvd - Published: 2026-08-23 19:16 - Updated: 2026-08-23 21:16

Severity

Summary

References

	URL	Tags
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L386-399
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L654-666
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/changes
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/source/Proxy.xs#L400-426
	af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2026/08/23/2

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "modules": [
            "Reverse::Proxy"
          ],
          "packageName": "Reverse-Proxy",
          "packageURL": "pkg:cpan/Reverse-Proxy",
          "programFiles": [
            "Proxy.xs"
          ],
          "programRoutines": [
            {
              "name": "rp_target_url"
            },
            {
              "name": "rp_raw_request"
            }
          ],
          "versions": [
            {
              "lessThan": "0.04",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line.\n\nPSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, \u0027?\u0027 or \u0027#\u0027 truncates it the same way.\n\nEverything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy\u0027s own routing does not expose."
    }
  ],
  "id": "CVE-2026-75922",
  "lastModified": "2026-08-23T21:16:28.150",
  "metrics": {},
  "published": "2026-08-23T19:16:28.930",
  "references": [
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L386-399"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L654-666"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/changes"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/source/Proxy.xs#L400-426"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/23/2"
    }
  ],
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-93"
        },
        {
          "lang": "en",
          "value": "CWE-444"
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "type": "Secondary"
    }
  ]
}

GHSA-5XQ5-HX4G-F5V6

Vulnerability from github – Published: 2026-08-23 21:31 – Updated: 2026-08-23 21:31

Details

Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line.

PSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, '?' or '#' truncates it the same way.

Everything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy's own routing does not expose.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-75922"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-93"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-23T19:16:28Z",
    "severity": null
  },
  "details": "Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line.\n\nPSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, \u0027?\u0027 or \u0027#\u0027 truncates it the same way.\n\nEverything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy\u0027s own routing does not expose.",
  "id": "GHSA-5xq5-hx4g-f5v6",
  "modified": "2026-08-23T21:31:00Z",
  "published": "2026-08-23T21:31:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-75922"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L386-399"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L654-666"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/changes"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/source/Proxy.xs#L400-426"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/23/2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-75922 (GCVE-0-2026-75922)

FKIE_CVE-2026-75922

GHSA-5XQ5-HX4G-F5V6

Tags

Sightings

Nomenclature