CVE-2026-34518 — Sensitive Information Exposure in Aiohttp

CWE-200 — Sensitive Information ExposureCWE-497 — Exposure of Sensitive System Information to an Unauthorized Control Sphere9 documents8 sources
Severity
2.7LOWNVD
EPSS
0.1%
top 83.67%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Aio-libs AiohttpAiohttp
Timeline
PublishedApr 1

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.

CVSS vector

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

Affected Packages2 packages

▶PyPIaiohttp/aiohttp< 3.13.4
▶CVEListV5aio-libs/aiohttp< 3.13.4

🔴Vulnerability Details

4
GHSA
AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect↗2026-04-01
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OSV
AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect↗2026-04-01
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CVEList
AIOHTTP: Cookie and Proxy-Authorization headers leaked on cross-origin redirect↗2026-04-01
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OSV
CVE-2026-34518: AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python↗2026-04-01
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📋Vendor Advisories

2
Red Hat
aiohttp: AIOHTTP: Information disclosure via retained Cookie and Proxy-Authorization headers during redirects↗2026-04-01
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Debian
CVE-2026-34518: python-aiohttp - AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. ...↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-34518 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-34518 — Sensitive Information Exposure | cvebase