{"id":"CVE-2026-103261","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-103261","generatedAt":"2026-10-28T01:48:05.064Z","title":"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.","description":"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":"2026-10-01T11:17:21.000Z","lastModified":"2026-10-01T15:17:27.000Z","status":"Deferred","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":6.9,"severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-770"],"affected":[],"epss":{"score":0.00467,"percentile":0.40186,"date":"2026-10-26","history":[{"date":"2026-10-02","score":0.00467,"percentile":0.38202}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.47%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-01T11:17:21.000Z","detail":{"score":"6.9","severity":"MEDIUM","publishedAt":"2026-10-01T11:17:20.847Z"},"summary":"New CVE, medium severity (CVSS 6.9)."}],"references":[{"url":"https://github.com/tornadoweb/tornado/commit/03945136ea9746eccf61caf88edae39642e59c93","source":"disclosure@vulncheck.com"},{"url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-3hv7-mjh2-fv65","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-query-string","source":"disclosure@vulncheck.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-103261","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}