CVE-2026-54275

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.

CVSS 4.0

2.7CVSS: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

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 40% of CVEs (scores of 2026-10-25)

CWE

CWE-297

Published

2026-06-22

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Affected

• aiohttp:aiohttp

Packages (OSV)

References

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

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