{"id":"CVE-2026-31958","title":"Tornado is a Python web framework and asynchronous networking library","summary":"Tornado is a Python web framework and asynchronous networking library. In versions of Tornado prior to 6.5.5, the only limit on the number of parts in multipart/form-data is the max_body_size setting (default 100MB). Since parsing occurs…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-400","CWE-770"],"vendor":"tornadoweb","product":"tornado","affected":["tornado < 6.5.5"],"patched":["tornado 6.5.5"],"published":"2026-03-11","updated":"2026-06-17","sourceUpdated":"2026-06-17T10:34:50.473","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-31958","references":[{"url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc","label":"security-advisories@github.com"},{"url":"https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31958.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-31958"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2446765"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-31958"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31958"},{"url":"https://access.redhat.com/errata/RHSA-2026:24342"},{"url":"https://access.redhat.com/errata/RHSA-2026:20577"},{"url":"https://access.redhat.com/errata/RHSA-2026:13641"},{"url":"https://access.redhat.com/errata/RHSA-2026:19034"},{"url":"https://access.redhat.com/errata/RHSA-2026:20573"},{"url":"https://access.redhat.com/errata/RHSA-2026:20810"},{"url":"https://access.redhat.com/errata/RHSA-2026:20572"},{"url":"https://access.redhat.com/errata/RHSA-2026:13670"},{"url":"https://access.redhat.com/errata/RHSA-2026:19189"},{"url":"https://access.redhat.com/errata/RHSA-2026:8093"},{"url":"https://access.redhat.com/errata/RHSA-2026:11493"},{"url":"https://access.redhat.com/errata/RHSA-2026:11494"},{"url":"https://access.redhat.com/errata/RHSA-2026:11495"},{"url":"https://access.redhat.com/errata/RHSA-2026:11454"},{"url":"https://access.redhat.com/errata/RHSA-2026:10184"},{"url":"https://access.redhat.com/errata/RHSA-2026:24977"},{"url":"https://access.redhat.com/errata/RHSA-2026:37275"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-03-12T19:55:43.911671Z"},"scores":{"nvd":7.5,"cna":8.7,"vendor":5.3},"ingestedAt":"2026-09-13T09:17:31.290Z","epss":0.00375,"epssPercentile":0.31364,"slug":"CVE-2026-31958","body":"## Overview\n\nTornado is a Python web framework and asynchronous networking library. In versions of Tornado prior to 6.5.5, the only limit on the number of parts in multipart/form-data is the max_body_size setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very large multipart bodies with many parts. This vulnerability is fixed in 6.5.5.\n\n## Affected\n\n- `tornado < 6.5.5`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `tornado 6.5.5`\n\n## Vendor advisories\n\n- **RHSA-2026:24342** · Red Hat · fixed in: Red Hat Enterprise Linux Server Optional (v. 7 ELS) · released 2026-06-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:24342)\n- **RHSA-2026:20577** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20577)\n- **RHSA-2026:13641** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-05-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:13641)\n- **RHSA-2026:19034** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19034)\n- **RHSA-2026:20573** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20573)\n- **RHSA-2026:20810** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.4) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20810)\n- **RHSA-2026:20572** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20572)\n- **RHSA-2026:13670** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-05-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:13670)\n- **RHSA-2026:19189** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19189)\n- **RHSA-2026:8093** · Red Hat · fixed in: Red Hat Enterprise Linux HighAvailability (v. 8), Red Hat Enterprise Linux ResilientStorage (v. 8) · released 2026-04-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:8093)\n- **RHSA-2026:11493** · Red Hat · fixed in: Red Hat Enterprise Linux High Availability AUS (v.8.4), Red Hat Enterprise Linux HighAvailability EUS EXTENSION (v.8.4) · released 2026-04-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:11493)\n- **Red Hat VEX** · Moderate · affected: Lightspeed Core, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat OpenShift AI (RHOAI) · no fix planned: Red Hat OpenShift AI (RHOAI), Lightspeed Core, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux AI (RHEL AI) 3 · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31958.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}