PYSEC-2026-1104

Vulnerability from pysec - Published: 2026-07-07 16:02 - Updated: 2026-07-07 17:23
VLAI
Details

Summary

The Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request.

Impact

If a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections.

Patch: https://github.com/aio-libs/aiohttp/commit/e8d774f635dc6d1cd3174d0e38891da5de0e2b6a

Severity
1.7 (Low)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U
Impacted products
Name purl
aiohttp pkg:pypi/aiohttp
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "aiohttp",
        "purl": "pkg:pypi/aiohttp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.12.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
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        "3.9.0b1",
        "3.9.0rc0",
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      ]
    }
  ],
  "aliases": [
    "CVE-2025-53643",
    "GHSA-9548-qrrj-x5pj"
  ],
  "details": "### Summary\nThe Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request.\n\n### Impact\nIf a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections.\n\n----\n\nPatch: https://github.com/aio-libs/aiohttp/commit/e8d774f635dc6d1cd3174d0e38891da5de0e2b6a",
  "id": "PYSEC-2026-1104",
  "modified": "2026-07-07T17:23:37.007122Z",
  "published": "2026-07-07T16:02:58.017770Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-9548-qrrj-x5pj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-53643"
    },
    {
      "type": "FIX",
      "url": "https://github.com/aio-libs/aiohttp/commit/e8d774f635dc6d1cd3174d0e38891da5de0e2b6a"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/aio-libs/aiohttp"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/aiohttp"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-9548-qrrj-x5pj"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": " AIOHTTP is vulnerable to HTTP Request/Response Smuggling through incorrect parsing of chunked trailer sections"
}



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