{"id":"CVE-2026-103261","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-103261","summary":"Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with…","details":"Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.","published":"2026-10-01T11:17:20.847","modified":"2026-10-01T11:17:20.997","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/tornadoweb/tornado/commit/03945136ea9746eccf61caf88edae39642e59c93","label":"tornadoweb/tornado@0394513"},"references":[{"type":"WEB","url":"https://github.com/tornadoweb/tornado/commit/03945136ea9746eccf61caf88edae39642e59c93"},{"type":"WEB","url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-3hv7-mjh2-fv65"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-query-string"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-10-01T11:17:20.997"}}