CVE-2026-54275

AIOHTTP: TLS Server Hostname Override Is Ignored When Reusing HTTPS Connections

State: Published
Severity: 2.7 Low
Published: Jun 22, 2026
Updated: Jun 22, 2026
Reserved: Jun 12, 2026

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, the server_hostname TLS SNI check can be bypassed when an existing connection is reused. If an application makes multiple requests to the same domain, but with different per-request server_hostname parameters, then the later calls may succeed by reusing the existing connection when they should have been rejected due to the TLS SNI check. This vulnerability is fixed in 3.14.1.

Scores

CVSS	Score	Vector	Source
4.0	2.7 Low	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/E:U	GitHub_M

Weaknesses

CWE-297 Improper Validation of Certificate with Host Mismatch

Affected Products

Product	Versions
aiohttpaio-libs	< 3.14.1Affected

References

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

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