AIOHTTP has CRLF injection through multipart part content type header construction

Description

Summary

An attacker who controls the content_type parameter in aiohttp could use this to inject extra headers or similar exploits.

Impact

If an application allows untrusted data to be used for the multipart content_type parameter when constructing a request, an attacker may be able to manipulate the request to send something other than what the developer intended.


Patch: https://github.com/aio-libs/aiohttp/commit/9a6ada97e2c6cf1ce31727c6c9fcea17c21f6f06

Basic information

Type
reviewed
Severity
low
Advisory on GitHub
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Repository advisory
Open repository advisory ↗
Source code
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Published (advisory)
2026-04-01 21:20:06 UTC
Updated
2026-04-06 16:46:52 UTC
GitHub reviewed
2026-04-01 21:20:06 UTC
NVD published
2026-04-01

EPSS Score

Score Percentile
0.04% 11.69%

CVSS Scores

Base score Version Severity Vector
2.7 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 Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L)
Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:U)
Unreported: no public PoC, no reported exploitation, and no known simplification tools.

Identifiers

CWEs

CWE id Name
CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

Credits

  • mingijunggrape (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip aiohttp <= 3.13.3 3.13.4

References

cvelogic Threat Intelligence