CVE-2026-49854
Tornado: Out-of-bounds memory access in C extension
MEDIUM 5.3
At a glance
- Source
- NVD
- EPSS
- EPSS 0.42 % · percentile 36 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Deferred
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.
Weaknesses (CWE)
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | GitHub_M |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-cx3h-4qpv-8hc9 — Tornado has out-of-bounds memory access via C extension
- PYSEC-2026-3388 — Tornado has out-of-bounds memory access via C extension
European references
- ENISA EUVD · EUVD-2026-44504
- GCVE · GCVE-0-2026-49854
Affected products
| Product | Versions |
|---|---|
| tornadoweb · tornado | affected < 6.5.6 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |