Vulnerability-Lookup

GHSA-2PG6-44CX-C49V

Vulnerability from github – Published: 2026-07-09 23:19 – Updated: 2026-07-09 23:19

Summary

mint has potential CRLF injection in its HTTP request line via unvalidated `method`/`target`

Details

Summary

Mint's HTTP/1 request encoder splices the caller-supplied method and target directly into the request line without character validation. An application that forwards attacker-controlled input as the HTTP method or the target to Mint.HTTP.request/5 is exposed to request-line CRLF injection, allowing the attacker to terminate the request line early, inject arbitrary headers, and pipeline a fully attacker-chosen second request onto the same TCP connection.

Details

encode_request_line/2 in lib/mint/http1/request.ex writes method and target to the wire verbatim. encode_headers/1 validates header names and values, but there is no equivalent validate_method!/1.

Mint 1.7.0 added validate_request_target/2, which rejects CRLF and other control characters in target by default and closes the path/query vector. The method field remains unvalidated, so a CRLF-bearing method such as "GET / HTTP/1.1\r\nX-Smuggled: 1\r\nGET /admin" is accepted and written to the socket as-is. Bytes after the first \r\n are interpreted by the peer as an injected header, or, with a second \r\n, as an additional pipelined request.

PoC

Stand up a Mint-using gateway/proxy that calls Mint.HTTP.request(conn, method, "/", [], nil) with method taken from caller input.
Send a request whose forwarded method is "GET / HTTP/1.1\r\nX-Smuggled-Header: pwned\r\nGET /admin/delete-everything".
Observe the bytes received by the upstream server: the smuggled header line and the second request line appear verbatim in the outbound stream.

Impact

CRLF injection / HTTP request smuggling in the HTTP/1 client encoder, exploitable under default configuration whenever an application passes caller-influenced input as the HTTP method. An attacker who controls the method can inject arbitrary outbound headers (forged Host, Authorization, cache-poisoning headers) and smuggle additional, fully attacker-chosen requests to the upstream server over the same connection, potentially reaching endpoints the legitimate caller never intended to invoke.

Resources

Introduction commit: https://github.com/elixir-mint/mint/commit/8db1acff30b6a9433762c18b1e1f891b8c1f74f7
Patch commit: https://github.com/elixir-mint/mint/commit/fad091454cbb7449b19edb8e1fee12ca7cf28c3a

Severity

2.1 (Low)


                  
                    CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Hex",
        "name": "mint"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.9.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-48861"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-93"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-09T23:19:12Z",
    "nvd_published_at": "2026-06-02T16:16:44Z",
    "severity": "LOW"
  },
  "details": "### Summary\n\nMint\u0027s HTTP/1 request encoder splices the caller-supplied `method` and `target` directly into the request line without character validation. An application that forwards attacker-controlled input as the HTTP method or the target to `Mint.HTTP.request/5` is exposed to request-line CRLF injection, allowing the attacker to terminate the request line early, inject arbitrary headers, and pipeline a fully attacker-chosen second request onto the same TCP connection.\n\n### Details\n\n`encode_request_line/2` in `lib/mint/http1/request.ex` writes `method` and `target` to the wire verbatim. `encode_headers/1` validates header names and values, but there is no equivalent `validate_method!/1`.\n\nMint 1.7.0 added `validate_request_target/2`, which rejects CRLF and other control characters in `target` by default and closes the path/query vector. The `method` field remains unvalidated, so a CRLF-bearing method such as `\"GET / HTTP/1.1\\r\\nX-Smuggled: 1\\r\\nGET /admin\"` is accepted and written to the socket as-is. Bytes after the first `\\r\\n` are interpreted by the peer as an injected header, or, with a second `\\r\\n`, as an additional pipelined request.\n\n### PoC\n\n1. Stand up a Mint-using gateway/proxy that calls `Mint.HTTP.request(conn, method, \"/\", [], nil)` with `method` taken from caller input.\n2. Send a request whose forwarded method is `\"GET / HTTP/1.1\\r\\nX-Smuggled-Header: pwned\\r\\nGET /admin/delete-everything\"`.\n3. Observe the bytes received by the upstream server: the smuggled header line and the second request line appear verbatim in the outbound stream.\n\n### Impact\n\nCRLF injection / HTTP request smuggling in the HTTP/1 client encoder, exploitable under default configuration whenever an application passes caller-influenced input as the HTTP method. An attacker who controls the method can inject arbitrary outbound headers (forged `Host`, `Authorization`, cache-poisoning headers) and smuggle additional, fully attacker-chosen requests to the upstream server over the same connection, potentially reaching endpoints the legitimate caller never intended to invoke.\n\n## Resources\n\n* Introduction commit: https://github.com/elixir-mint/mint/commit/8db1acff30b6a9433762c18b1e1f891b8c1f74f7\n* Patch commit: https://github.com/elixir-mint/mint/commit/fad091454cbb7449b19edb8e1fee12ca7cf28c3a",
  "id": "GHSA-2pg6-44cx-c49v",
  "modified": "2026-07-09T23:19:12Z",
  "published": "2026-07-09T23:19:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/elixir-mint/mint/security/advisories/GHSA-2pg6-44cx-c49v"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48861"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-mint/mint/commit/fad091454cbb7449b19edb8e1fee12ca7cf28c3a"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-48861.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/elixir-mint/mint"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-48861"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "mint has potential CRLF injection in its HTTP request line via unvalidated `method`/`target`"
}

CVE-2026-48861 (GCVE-0-2026-48861)

Vulnerability from cvelistv5 – Published: 2026-06-02 14:15 – Updated: 2026-06-02 19:14

Title

CRLF injection in HTTP/1 request line via unvalidated method in Mint

Summary

Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling. In lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: [method, ?\s, target, " HTTP/1.1\r\n"]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection. Mint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip_target_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions. This issue affects mint: from 0.1.0 before 1.9.0.

Severity

2.1 (Low)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')

Assigner

EEF

References

4 references

URL	Tags
https://github.com/elixir-mint/mint/security/advi…	vendor-advisoryrelated
https://cna.erlef.org/cves/CVE-2026-48861.html	related
https://osv.dev/vulnerability/EEF-CVE-2026-48861	related
https://github.com/elixir-mint/mint/commit/fad091…	patch

Impacted products

2 products

Vendor	Product	Version
elixir-mint	mint	Affected: 0.1.0 , < 1.9.0 (semver) cpe:2.3:a:elixir-mint:mint::::::::
elixir-mint	mint	Affected: 8db1acff30b6a9433762c18b1e1f891b8c1f74f7 , < fad091454cbb7449b19edb8e1fee12ca7cf28c3a (git) cpe:2.3:a:elixir-mint:mint::::::::

Credits

Peter Ullrich Eric Meadows-Jönsson Jonatan Männchen / EEF

Show details on NVD website

JSON

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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.

Action not permitted

GHSA-2PG6-44CX-C49V

Summary

Details

PoC

Impact

Resources

CVE-2026-48861 (GCVE-0-2026-48861)

Tags

Sightings

Nomenclature