CVE-2026-49853

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.

CVSS 3.1

7.7CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 38% of CVEs (scores of 2026-10-25)

CWE

CWE-200

Published

2026-07-14

Modified

2026-10-24

Record from

the NVD, synced 2026-10-25

Packages (OSV)

References

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

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