Improper Certificate Validation in aiohttp - CVE-2026-54275

Vulnerability identifier: #VU133990

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-54275

CWE-ID: CWE-295

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to bypass TLS hostname verification.

The vulnerability exists due to improper certificate validation in HTTPS connection reuse when reusing an existing connection for later requests with different per-request server_hostname parameters. A remote attacker can cause connection reuse to bypass TLS hostname verification.

aiohttp
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Desktop 15
SUSE Manager Server
SUSE Manager Proxy
SUSE Manager Retail Branch Server
Public Cloud Module
Python 3 Module
openSUSE Leap
openEuler
python-aiohttp-debugsource
python3-aiohttp-debuginfo
python3-aiohttp
python311-aiohttp
python311-aiohttp-debuginfo
python-aiohttp
python-aiohttp-debuginfo
python-aiohttp-help

Install security update from vendor's website.

aiohttp - update to 3.14.1
python-aiohttp-debugsource - addressed in versions 3.6.0-150100.3.38.1, 3.9.3-150400.10.43.1
python3-aiohttp-debuginfo - update to 3.6.0-150100.3.38.1
python3-aiohttp - update to 3.6.0-150100.3.38.1
python311-aiohttp - update to 3.9.3-150400.10.43.1
python311-aiohttp-debuginfo - update to 3.9.3-150400.10.43.1
python-aiohttp - update to 3.14.1-1
python-aiohttp-debuginfo - update to 3.14.1-1
python-aiohttp-debugsource - update to 3.14.1-1
python-aiohttp-help - update to 3.14.1-1
python3-aiohttp - update to 3.14.1-1

• https://github.com/aio-libs/aiohttp/security/advisories/GHSA-4m7w-qmgq-4wj5
• https://github.com/aio-libs/aiohttp/commit/0ca2b6c28a25726527a8b60f25960262a91ed0e0

• Multiple vulnerabilities in aiohttp
• openEuler 24.03 LTS SP1 update for python-aiohttp
• openEuler 24.03 LTS SP3 update for python-aiohttp
• SUSE update for python-aiohttp
• SUSE update for python-aiohttp