Connect your agent
AdvisoriesCriticalCheck your lockfilePluginHow it worksPricing Connect your agent

Advisory record · GHSA-45c4-8wx5-qw6w

aiohttp.web.Application vulnerable to HTTP request smuggling via llhttp HTTP request parser

CVSS 5.3 MediumEPSS 0.013 · 71st percentile

Published by the GitHub Advisory Database at 20 Jul 2023, 14:52 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
aiohttpPyPI<3.8.53.8.5
Identifiers
GHSA-45c4-8wx5-qw6w · CVE-2023-37276 · PYSEC-2023-120
Weakness (CWE)
CWE-444
Tags
Published
20 Jul 2023
Updated
10 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The aiohttp package before 3.8.5 is vulnerable to HTTP request smuggling when used as an HTTP server, because its bundled llhttp request parser misreads certain header values. A remote attacker can send a crafted HTTP request to cause this smuggling. Upgrade aiohttp to version 3.8.5 or later; if that is not possible, reinstall aiohttp with the AIOHTTP_NO_EXTENSIONS=1 environment variable to use the pure Python parser instead.

Written 5 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
5.3 Medium 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.013, the 71st percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:37 UTC First seen by agentprime
  2. 31 Oct 2026, 14:37 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.