Information disclosure in aiohttp - CVE-2026-34518
Published: April 26, 2026
Vulnerability identifier: #VU127949
CSH Severity: Medium
CVSS v4.0: 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/U:Green
CVE-ID: CVE-2026-34518
CWE-ID: CWE-200
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: aio-libs
Affected software:
aiohttp
aiohttp
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to exposure of sensitive information in redirect handling when following redirects to a different origin. A remote attacker can trigger a cross-origin redirect to disclose sensitive information.
Cookie and Proxy-Authorization headers are retained while the Authorization header is dropped during the redirect.
How to mitigate CVE-2026-34518
Install security update from vendor's website.