{"cve":"CVE-2026-49854","nvd":{"published":"2026-07-14T21:17:02.300","modified":"2026-10-24T21:10:00.130","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","score":5.3},"cwes":["CWE-126"],"references":["https://github.com/tornadoweb/tornado/commit/96dc88c2a05705287856b2cd6b4b4034f9a6aaac","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-cx3h-4qpv-8hc9"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:06.907763985+00:00"},"epss":{"cve":"CVE-2026-49854","score":0.00419,"percentile":0.35942,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-cx3h-4qpv-8hc9","url":"https://osv.dev/vulnerability/GHSA-cx3h-4qpv-8hc9","summary":"Tornado has out-of-bounds memory access via C extension","modified":"2026-09-10T03:50:49.232529305Z","packages":[{"ecosystem":"PyPI","name":"tornado","purl":"pkg:pypi/tornado","ranges":["<6.5.6"],"fixed":["6.5.6"]}]},{"id":"PYSEC-2026-3388","url":"https://osv.dev/vulnerability/PYSEC-2026-3388","summary":"Tornado has out-of-bounds memory access via C extension","modified":"2026-07-13T16:33:26.790475442Z","packages":[{"ecosystem":"PyPI","name":"tornado","purl":"pkg:pypi/tornado","ranges":["<6.5.6"],"fixed":["6.5.6"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}