{"id":"CVE-2026-34525","summary":"AIOHTTP: Duplicate Host header accepted","details":"AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, multiple Host headers were allowed in aiohttp. This issue has been patched in version 3.13.4.","aliases":["GHSA-c427-h43c-vf67"],"modified":"2026-04-13T04:27:49.470945Z","published":"2026-04-01T20:28:46.652Z","related":["CGA-3qvr-m27f-v5v7"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-20","CWE-444"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34525.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34525.json"},{"type":"FIX","url":"https://github.com/aio-libs/aiohttp/commit/53e2e6fc58b89c6185be7820bd2c9f40216b3000"},{"type":"FIX","url":"https://github.com/aio-libs/aiohttp/commit/e00ca3cca92c465c7913c4beb763a72da9ed8349"},{"type":"WEB","url":"https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4"},{"type":"ADVISORY","url":"https://github.com/aio-libs/aiohttp/security/advisories/GHSA-c427-h43c-vf67"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34525"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/aio-libs/aiohttp","events":[{"introduced":"0"},{"fixed":"9f7c7ab6f2924824e4a61a3b5c5c36475f4e25c6"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"3.13.4"}]}}],"versions":["0.15.2","0.8.2","1.3.0","2.0.0","2.0.0rc1","4v0.21.6","v.0.6.5","v0.1","v0.10.0","v0.10.1","v0.11.0","v0.12.0","v0.13.0","v0.13.1","v0.14.0","v0.14.1","v0.14.2","v0.14.3","v0.14.4","v0.15.0","v0.15.1","v0.15.2","v0.15.3","v0.16.0","v0.16.1","v0.16.2","v0.16.3","v0.17.0","v0.18.0","v0.19.0","v0.2","v0.20.0","v0.20.1","v0.21.0","v0.22.0","v0.22.0b0","v0.22.0b1","v0.22.0b2","v0.22.0b3","v0.22.0b4","v0.22.0b5","v0.22.0b6","v0.22.1","v0.3","v0.4","v0.4.1","v0.4.2","v0.5.0","v0.6.1","v0.6.2","v0.6.3","v0.6.4","v0.7.0","v0.7.1","v0.7.2","v0.7.3","v0.8.0","v0.8.1","v0.8.3","v0.8.4","v0.9.0","v0.9.1","v0.9.2","v1.0.0","v1.0.1","v1.1.0","v1.1.1","v1.2.0","v2.1.0","v2.2.0","v2.3.0","v2.3.0a1","v2.3.0a2","v2.3.0a3","v2.3.0a4","v3.0.0b0","v3.0.0b1","v3.0.0b2","v3.0.0b3","v3.0.0b4","v3.1.0","v3.10.0","v3.10.0b0","v3.10.0b1","v3.10.0rc0","v3.11.0","v3.11.0b0","v3.11.0b1","v3.11.0b2","v3.11.0b3","v3.11.0b4","v3.11.0b5","v3.11.0rc0","v3.11.0rc1","v3.11.0rc2","v3.12.0","v3.12.0b0","v3.12.0b1","v3.12.0b2","v3.12.0b3","v3.12.0rc0","v3.12.0rc1","v3.13.0","v3.13.1","v3.13.2","v3.13.3","v3.2.0","v3.4.0","v3.4.0a0","v3.4.0a3","v3.4.0b1","v3.4.0b2","v3.5.0","v3.5.0a1","v3.5.0b1","v3.5.0b2","v3.5.0b3","v3.5.1","v3.5.2","v3.5.3","v3.5.4","v3.6.0","v3.6.0a0","v3.6.0a1","v3.6.0a10","v3.6.0a11","v3.6.0a12","v3.6.0a2","v3.6.0a3","v3.6.0a4","v3.6.0a5","v3.6.0a6","v3.6.0a7","v3.6.0a8","v3.6.0a9","v3.6.0b0","v3.6.1","v3.6.1b3","v3.6.1b4","v3.6.2","v3.6.2a1","v3.6.2a2","v3.7.0","v3.7.0b0","v3.7.0b1","v3.7.1","v3.8.0","v3.9.0","v3.9.0b0","v3.9.0b1","v3.9.0rc0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-34525.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"}]}