🛡️ CVE-2026-50269 — aiohttp

🟢 CVSS 2.0 — Low ✅ No Known Exploit CWE-113 OSV
2.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

aiohttp: CRLF injection in multipart headers

Summary

Attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar.

Impact

In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request.

Workaround

Sanitise such user input.

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Patch: https://github.com/aio-libs/aiohttp/commit/bf88077ebb14f4c29924b8e8904cba20c55c28b8

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. Rated impact: confidentiality none, integrity low, availability none.

Weakness class

CVE-2026-50269 is classified as CWE-113: HTTP Response Splitting. Unescaped input reaches an HTTP header, letting an attacker inject line breaks and forge additional headers or responses.

Affected software

CVE-2026-50269 is recorded against 1 package.

  • aiohttp (fixed in 3.14.0)

Timeline and source

Published on 15 June 2026 and last revised on 13 July 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Web)
github.com (Web)
github.com (Package)

Details

Severity LOW
CVSS Score 2.0
CVSS Vector 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
CWE CWE-113
Public Exploit ✅ No
Source OSV
Published 2026-06-15
Updated 2026-08-12
Modified 2026-07-13

Affected Packages

Software From version Fixed in
aiohttp — 3.14.0

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