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Advisory record · GHSA-m6qw-4cw2-hm4m

aiohttp: CRLF injection in multipart headers

CVSS 2.7 LowEPSS 0.0053 · 45th percentile

Published by the GitHub Advisory Database at 15 Jun 2026, 20:07 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
aiohttpPyPI<3.14.03.14.0
Identifiers
GHSA-m6qw-4cw2-hm4m · CVE-2026-50269 · PYSEC-2026-2106
Weakness (CWE)
CWE-93 · CWE-113
Tags
Published
15 Jun 2026
Updated
10 Sept 2026

Machine-written summary

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

aiohttp versions before 3.14.0 are vulnerable to CRLF injection in multipart headers. An attacker can exploit this only if the application passes user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, and can then inject additional headers or alter the request contents. Upgrade to aiohttp 3.14.0 or later; until then, sanitise any user input used in those headers.

Written 1 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
2.7 Low 4.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0053, the 45th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 4 Jun 2026, 14:41 UTC Published by the maintainers as a GitHub repository advisory
  2. 31 Oct 2026, 14:11 UTC First seen by agentprime
  3. 31 Oct 2026, 14:11 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.