What’s Vulnerable › Vulnerabilities
CVE-2024-23829: aiohttp's HTTP parser (the python one, not llhttp) still overly lenient about separators
- Severity: medium (CVSS 6.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.0% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2024-01-29 · updated 2026-06-17
- Weakness: CWE-444
Description
aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Security-sensitive parts of the Python HTTP parser retained minor differences in allowable character sets, that must trigger error handling to robustly match frame boundaries of proxies in order to protect against injection of additional requests. Additionally, validation could trigger exceptions that were not handled consistently with processing of other malformed input. Being more lenient than internet standards require could, depending on deployment environment, assist in request smuggling. The unhandled exception could cause excessive resource consumption on the application server and/or its logging facilities. This vulnerability exists due to an incomplete fix for CVE-2023-47627. Version 3.9.2 fixes this vulnerability.
Affected products
- aio-libs aiohttp: before 3.9.2 — fixed in 3.9.2
- Fedoraproject Fedora: 39
- Pypi Aiohttp: before 3.9.2; 0.1, 0.10.0, 0.10.1, 0.10.2, 0.11.0, 0.12.0 (+220) — fixed in 3.9.2
How to fix
Upgrade to a fixed version: aio-libs aiohttp 3.9.2; Pypi Aiohttp 3.9.2. Check the vendor advisory for mitigations.
References
- https://github.com/aio-libs/aiohttp/commit/33ccdfb0a12690af5bb49bda2319ec0907fa7827
- https://github.com/aio-libs/aiohttp/pull/8074
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-8qpw-xqxj-h4r2
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ICUOCFGTB25WUT336BZ4UNYLSZOUVKBD/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXWVZIVAYWEBHNRIILZVB3R3SDQNNAA7/
- https://github.com/aio-libs/aiohttp/commit/33ccdfb0a12690af5bb49bda2319ec0907fa7827
- https://github.com/aio-libs/aiohttp/pull/8074
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-8qpw-xqxj-h4r2
- https://lists.debian.org/debian-lts-announce/2025/02/msg00002.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ICUOCFGTB25WUT336BZ4UNYLSZOUVKBD/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXWVZIVAYWEBHNRIILZVB3R3SDQNNAA7/
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