VulnerabilityAnalyzed

CVE-2026-50269

Prior to 3.14.0, attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar.

LOW 2.7EPSS 0.30%

Does this matter?

Lower severity and a low EPSS score (0.30%). Track it; it rarely justifies an emergency change on its own.

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.0, attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar. 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. This vulnerability is fixed in 3.14.0.

CVSS 4.0: 2.7 LOWCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.30% probability · 23th percentile
CISA KEV: Not listed
Weakness: CWE-93, CWE-113
Affected: aiohttp/aiohttp
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.