CVE-2026-34518

Name: CVE-2026-34518
Creator: NVD / NIST
Published: 2026-04-01T21:17:00.02+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 2.7/10EPSS 0.34%

Last modified Jun 17, 2026

CVE-2026-34518 is a low-severity vulnerability rated 2.7/10 on the CVSS scale. AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, when following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. EPSS estimates a 0.34% chance of exploitation in the next 30 days.

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, when following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. This issue has been patched in version 3.13.4.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS 4.0

2.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.34%

25.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-200

Affected Software

Vendor	Product	Versions
Aiohttp	Aiohttp	< 3.13.4

References

https://github.com/aio-libs/aiohttp/commit/5351c980dcec7ad385730efdf4e1f4338b24fdb6Patch
https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4Release Notes
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-966j-vmvw-g2g9Patch, Vendor Advisory

Timeline

Published: Apr 1, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-34518?

How severe is CVE-2026-34518?

CVE-2026-34518 has a CVSS score of 2.7/10 (LOW severity). The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.

How do I fix CVE-2026-34518?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34518?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST