{"id":"CVE-2025-53643","aliases":["GHSA-9548-qrrj-x5pj","PYSEC-2026-1104"],"url":"https://o3.security/vulnerability/CVE-2025-53643","summary":"AIOHTTP is vulnerable to HTTP Request/Response Smuggling through incorrect parsing of chunked trailer sections","details":"AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.12.14, the Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request. 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. Version 3.12.14 contains a patch for this issue.","published":"2025-07-14T20:17:18.247Z","modified":"2026-08-12T03:51:13.865323229Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"aiohttp","fixedVersion":"3.12.14"}],"fix":{"url":"https://github.com/aio-libs/aiohttp/commit/e8d774f635dc6d1cd3174d0e38891da5de0e2b6a","label":"aio-libs/aiohttp@e8d774f"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/53xxx/CVE-2025-53643.json"},{"type":"ADVISORY","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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:13.865323229Z"}}