CVE-2026-49854

medium

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.

References

https://github.com/tornadoweb/tornado/security/advisories/GHSA-cx3h-4qpv-8hc9

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

https://github.com/tornadoweb/tornado/pull/3626

https://github.com/tornadoweb/tornado/commit/96dc88c2a05705287856b2cd6b4b4034f9a6aaac

Details

Source: Mitre, NVD

Published: 2026-07-14

Updated: 2026-07-15

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 5.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Severity: Medium

EPSS

EPSS: 0.00036