Asynchronous HTTP Client Framework Vulnerability in AIOHTTP by aio-libs
CVE-2026-34519

2.7LOW

Key Information:

Vendor

Aio-libs

Status
Aiohttp
Vendor
CVE Published:
1 April 2026

What is CVE-2026-34519?

A vulnerability exists in AIOHTTP, an asynchronous HTTP framework for Python, which allows an attacker controlling the 'reason' parameter in Response creation to inject unauthorized headers or carry out similar exploits. This vulnerability has been resolved in version 3.13.4, thus users are advised to update their AIOHTTP installations to this version or later to mitigate the risk.

Affected Version(s)

aiohttp < 3.13.4

References

https://github.com/aio-libs/aiohttp/security/advisories/G...
x_refsource_CONFIRM
https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c3...
x_refsource_MISC
https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
x_refsource_MISC

CVSS V4

Score:
2.7
Severity:
LOW
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.