{"id":"CVE-2026-49853","aliases":["GHSA-3x9g-8vmp-wqvf","PYSEC-2026-3387"],"url":"https://o3.security/vulnerability/CVE-2026-49853","summary":"Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient","details":"Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, SimpleAsyncHTTPClient shallow-copied redirected requests and removed only the Host header, leaving Authorization, auth_username, auth_password, and auth_mode in place when a redirect changed scheme, host, or port. This issue is fixed in version 6.5.6.","published":"2026-07-14T20:41:32.075Z","modified":"2026-08-12T03:51:37.350012129Z","cvss":{"score":7.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},"epss":{"score":0.00365,"percentile":0.29157,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"tornado","fixedVersion":"6.5.6"}],"fix":{"url":"https://github.com/tornadoweb/tornado/commit/aba2569f7ed7a6bdbef816658fb6b7182531b751","label":"tornadoweb/tornado@aba2569"},"references":[{"type":"WEB","url":"https://github.com/tornadoweb/tornado/releases/tag/v6.5.6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49853.json"},{"type":"ADVISORY","url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-3x9g-8vmp-wqvf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49853"},{"type":"FIX","url":"https://github.com/tornadoweb/tornado/commit/aba2569f7ed7a6bdbef816658fb6b7182531b751"},{"type":"FIX","url":"https://github.com/tornadoweb/tornado/pull/3626"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:37.350012129Z"}}