Medium [CVE-2026-54275] TLS SNI check bypass via connection reuse
This medium-severity Red Hat Linux advisory covers CVE-2026-54275 affecting Exploit Intelligence, Migration Toolkit for Applications 8, OpenShift Lightspeed.
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Summary
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.
This vulnerability is fixed in 3.14.1. This vulnerability allows a remote attacker to bypass the Transport Layer Security (TLS) Server Name Indication (SNI) check.
This occurs when an application reuses an existing connection for multiple requests to the same domain but with different server_hostname parameters.
Consequently, later requests may succeed by reusing the existing connection, even if they should have been rejected due to the TLS SNI check, potentially leading to unintended information disclosure or integrity issues.
Exploitation requires an application using aiohttp as an HTTPS client with connection pooling enabled, issuing multiple requests to the same host with differing server_hostname overrides. Many Red Hat products ship aiohttp as a bundled dependency without this usage pattern.
Affected packages should still be updated to aiohttp 3.14.1 or later when fixes are released. Red Hat severity: Moderate — CVSS 4.8 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N).
Weakness: CWE-367.
Affected products named by the advisory: Exploit Intelligence; Migration Toolkit for Applications 8; OpenShift Lightspeed; Red Hat AI Inference Server; and 6 more.
- < 3.14.1
Official advisory · high-confidence parse· fetched 15 days ago·verify at source
Mitigation checklist
- Update the aiohttp package to version 3.14.1 or later. Until updated builds are available, disable HTTP keep-alive (keep_alive) for aiohttp client sessions where per-request server_hostname TLS SNI overrides must be enforced between requests to the same host. Installations that do not use per-request server_hostname overrides, or that use aiohttp only as a server, are not affected by this flaw.
Official advisory · high-confidence parse· fetched 15 days ago·verify at source
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