---
schema_version: '1.0'
id: security-20260711-1e8734
url: https://osv.dev/vulnerability/GHSA-c427-h43c-vf67
url_hash: 1e8734f34390e92b4530af36dd58d78c5190bd44b5a925e74794af44256b8afa
canonical_url: https://osv.dev/vulnerability/GHSA-c427-h43c-vf67
source: osv:ghsa
category: security/library
category_raw: cve/library
region: null
tags:
- cve
- CVE-2026-34525
- GHSA-c427-h43c-vf67
- severity:CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N
- aiohttp
- PyPI
lang: en
published_at: '2026-04-01T21:49:45Z'
fetched_at: '2026-07-11T06:37:17Z'
updated_at: '2026-07-11T06:38:28Z'
status: published
content_hash: 2ca5d254a58c87f762a9d218aa6773ee6dfe609d417df2da1cab254cb1acef62
license_note: full
summary: AIOHTTP accepts duplicate Host headers
summary_source: rss
summary_en: AIOHTTP accepts duplicate Host headers
entities:
- name: Ghost
  type: UNKNOWN
key_facts: []
related: []
related_auto:
- name: agent_hermes
  type: person
  weight: 1.0
title: 'CVE-2026-34525: AIOHTTP accepts duplicate Host headers'
---

# CVE-2026-34525: AIOHTTP accepts duplicate Host headers

## TL;DR
AIOHTTP accepts duplicate Host headers

## Key Points
- cve / CVE-2026-34525 / GHSA-c427-h43c-vf67 / severity:CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N / aiohttp / PyPI

## Details
**Severity:** CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N
**Advisory:** GHSA-c427-h43c-vf67 (CVE-2026-34525)

**Affected (your watchlist):**
- `PyPI:aiohttp` 3.13.3 → fixed in 3.13.4 [docker/docker-strands]

**Details:**
### Summary

Multiple Host headers were allowed in aiohttp.

### Impact

Mostly this doesn't affect aiohttp security itself, but if a reverse proxy is applying security rules depending on the target Host, it is theoretically possible that the proxy and aiohttp could process different host names, possibly resulting in bypassing a security check on the proxy and getting a request processed by aiohttp in a privileged sub app when using `Application.add_domain()`.

-----

Patch: https://github.com/aio-libs/aiohttp/commit/e00ca3cca92c465c7913c4beb763a72da9ed8349
Patch: https://github.com/aio-libs/aiohttp/commit/53e2e6fc58b89c6185be7820bd2c9f40216b3000

**References:**
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-c427-h43c-vf67
- https://nvd.nist.gov/vuln/detail/CVE-2026-34525
- https://github.com/aio-libs/aiohttp/commit/53e2e6fc58b89c6185be7820bd2c9f40216b3000
- https://github.com/aio-libs/aiohttp/commit/e00ca3cca92c465c7913c4beb763a72da9ed8349
- https://github.com/aio-libs/aiohttp
- https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4

_Data: OSV.dev (upstream: ghsa) — https://osv.dev/vulnerability/GHSA-c427-h43c-vf67_

## Source
元記事: [CVE-2026-34525: AIOHTTP accepts duplicate Host headers](https://osv.dev/vulnerability/GHSA-c427-h43c-vf67) — published 2026-04-01T21:49:45Z