CVE-2026-49854

Description

Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, the optional native extension tornado.speedups implemented websocket_mask without validating that the mask argument is exactly four bytes, allowing the C function to read up to three bytes beyond the provided buffer when reached through Tornado XSRF token decoding with the native extension active. This issue is fixed in version 6.5.6.

PUBLISHED Reserved 2026-06-01 | Published 2026-07-14 | Updated 2026-07-14 | Assigner GitHub_M

Problem types

CWE-126: Buffer Over-read

Product status

References

github.com/...ornado/security/advisories/GHSA-cx3h-4qpv-8hc9

github.com/tornadoweb/tornado/pull/3626

github.com/...ommit/96dc88c2a05705287856b2cd6b4b4034f9a6aaac

github.com/tornadoweb/tornado/releases/tag/v6.5.6

cve.org (CVE-2026-49854)

nvd.nist.gov (CVE-2026-49854)

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