Medium 5.3Published Jul 14, 2026

CVE-2026-49854Tornado: Out-of-bounds memory access in C extension

Updated under an hour ago (Oct 27, 2026, 8:10 PM ET)

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Every CVE for tornadoweb tornado

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness (CWE): CWE-126
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jul 15, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

tornadoweb tornado tornadoweb:tornado (from the name)	before 6.5.6	CNA record

References

References

https://github.com/tornadoweb/tornado/security/advisories/GHSA-cx3h-4qpv-8hc9	x-refsource-confirm
https://github.com/tornadoweb/tornado/pull/3626	x-refsource-misc
https://github.com/tornadoweb/tornado/commit/96dc88c2a05705287856b2cd6b4b4034f9a6aaac	x-refsource-misc
https://github.com/tornadoweb/tornado/releases/tag/v6.5.6	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.