CVE-2026-49853

Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient

Description

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.

Scores

Weaknesses (CWE)

• CWE-200

Advisories

• GHSA-3x9g-8vmp-wqvf — Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient
• PYSEC-2026-3387 — Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient

European references

• ENISA EUVD · EUVD-2026-44503
• GCVE · GCVE-0-2026-49853

Affected products

References

• https://github.com/tornadoweb/tornado/security/advisories/GHSA-3x9g-8vmp-wqvf
• https://github.com/tornadoweb/tornado/pull/3626
• https://github.com/tornadoweb/tornado/commit/aba2569f7ed7a6bdbef816658fb6b7182531b751
• https://github.com/tornadoweb/tornado/releases/tag/v6.5.6

Sources