---
id: CVE-2026-54275
aliases:
  - GHSA-4m7w-qmgq-4wj5
  - PYSEC-2026-237
title: >-
  aiohttp: TLS Server Hostname Override Is Ignored When Reusing HTTPS
  Connections
summary: >-
  aiohttp: TLS Server Hostname Override Is Ignored When Reusing HTTPS
  Connections
severity: low
vendor: aiohttp
product: aiohttp
ecosystem: pip
affected:
  - aiohttp < 3.14.1
patched:
  - aiohttp 3.14.1
published: '2026-06-15'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:48.205198252Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-4m7w-qmgq-4wj5'
references:
  - url: >-
      https://github.com/aio-libs/aiohttp/security/advisories/GHSA-4m7w-qmgq-4wj5
  - url: 'https://github.com/aio-libs/aiohttp'
  - url: 'https://github.com/advisories/GHSA-4m7w-qmgq-4wj5'
tags:
  - osv
  - pip
  - ghsa
epss: 0.0047
epssPercentile: 0.38087
cwe:
  - CWE-297
ingestedAt: '2026-07-07T15:41:58.681Z'
---

## Overview

### Summary

The `server_hostname` TLS SNI check can be bypassed when an existing connection is reused.

### Impact

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.

### Workaround

Disable keep_alive if you need to change the `server_hostname` check between requests.

-----

Patch: https://github.com/aio-libs/aiohttp/commit/0ca2b6c28a25726527a8b60f25960262a91ed0e0

## Affected packages

- `aiohttp < 3.14.1`

## Remediation

Upgrade to a patched release:

- `aiohttp 3.14.1`