CVE-2026-34518
published 2026-04-01CVE-2026-34518: 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…
PriorityP429medium5.3CVSS 3.1
AVNACLPRNUINSUCLINAN
EPSS
0.34%
26.2th percentile
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.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| aio-libs | aiohttp | < 3.13.4 | 3.13.4 |
| aiohttp | aiohttp | < 3.13.4 | 3.13.4 |
| aiohttp | aiohttp | >= 0 < 3.13.4 | 3.13.4 |
| debian | python-aiohttp | — | — |
CVSS provenance
nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
nvdv4.02.7LOWCVSS: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
osv2.7LOW
vendor_debian2.7LOW
vendor_redhat2.7LOW
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GHSA
AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect
ghsa·2026-04-01
CVE-2026-34518 [LOW] CWE-200 AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect
AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect
### Summary
When following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers.
### Impact
The Cookie and Proxy-Authorizations headers could contain sensitive information which may be leaked to an unintended party after following a redirect.
Patch: https://github.com/aio-libs/aiohttp/commit/5351c980dcec7ad385730efdf4e1f4338b24fdb6
OSV
AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect
osv·2026-04-01
CVE-2026-34518 [LOW] AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect
AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect
### Summary
When following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers.
### Impact
The Cookie and Proxy-Authorizations headers could contain sensitive information which may be leaked to an unintended party after following a redirect.
Patch: https://github.com/aio-libs/aiohttp/commit/5351c980dcec7ad385730efdf4e1f4338b24fdb6
OSV
CVE-2026-34518: AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python
osv·2026-04-01·CVSS 2.7
CVE-2026-34518 [LOW] CVE-2026-34518: AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python
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.
Red Hat
aiohttp: AIOHTTP: Information disclosure via retained Cookie and Proxy-Authorization headers during redirects
vendor_redhat·2026-04-01·CVSS 2.7
CVE-2026-34518 [LOW] CWE-497 aiohttp: AIOHTTP: Information disclosure via retained Cookie and Proxy-Authorization headers during redirects
aiohttp: AIOHTTP: Information disclosure via retained Cookie and Proxy-Authorization headers during redirects
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.
A flaw was found in AIOHTTP, an asynchronous HTTP client/server framework for asyncio and Python. When AIOHTTP follows redirects to a different origin, it incorrectly retains sensitive Cookie and Proxy-Authorization headers. This oversight could lead to information disclosure, where these headers are sent to unintended third-party sites, potentially exposing user session data or authentica
Debian
CVE-2026-34518: python-aiohttp - AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. ...
vendor_debian·2026·CVSS 2.7
CVE-2026-34518 [LOW] CVE-2026-34518: python-aiohttp - AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. ...
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.
Scope: local
bookworm: open
bullseye: open
forky: open
sid: open
trixie: open
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-34518 aiohttp: AIOHTTP: Information disclosure via retained Cookie and Proxy-Authorization headers during redirects
bugzilla·2026-04-01·CVSS 2.7
CVE-2026-34518 [LOW] CVE-2026-34518 aiohttp: AIOHTTP: Information disclosure via retained Cookie and Proxy-Authorization headers during redirects
CVE-2026-34518 aiohttp: AIOHTTP: Information disclosure via retained Cookie and Proxy-Authorization headers during redirects
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.
Wiz
CVE-2026-34518 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 2.7
CVE-2026-34518 [LOW] CVE-2026-34518 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-34518 :
Wolfi vulnerability analysis and mitigation
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.
Source : NVD
## 2.7
Score
Published April 1, 2026
Severity LOW
CNA Score 2.7
Affected Technologies
Wolfi
Chainguard
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 16.4
Exploitation Probability (EPSS) 0.1
Affected packages and libraries
metaflow-service-fips
python-aiohttp
Sources
NVD
Chainguard Has Fix Added at: Apr 02, 202
2026-04-01
Published