{"id":"CVE-2026-116577","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-116577","generatedAt":"2026-10-28T10:47:57.295Z","title":"Tornado is a Python web framework and asynchronous networking library.","description":"Tornado is a Python web framework and asynchronous networking library. Prior to 6.6, Tornado's HTTP header parser accepts obsolete line folding and repeatedly concatenates short continuation lines, causing quadratic CPU consumption on the IOLoop thread. An unauthenticated client can submit a header block containing many obsolete line-folding continuations before application code runs, blocking other connections served by the process. The cost grows with max_header_size, and only availability is affected. This issue is fixed in version 6.6.","published":"2026-10-26T21:18:14.000Z","lastModified":"2026-10-26T21:18:15.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","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"},"cwe":["CWE-407","CWE-770"],"affected":[],"epss":{"score":0.00384,"percentile":0.32256,"date":"2026-10-27","history":[{"date":"2026-10-27","score":0.00384,"percentile":0.32256}]},"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 (0.38%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-26T21:18:14.000Z","detail":{"score":"5.3","severity":"MEDIUM","publishedAt":"2026-10-26T21:18:14.087Z"},"summary":"New CVE, medium severity (CVSS 5.3)."}],"references":[{"url":"https://github.com/tornadoweb/tornado/commit/1b7a1dc9f340f52de929852e8125aa12f25297c9","source":"security-advisories@github.com"},{"url":"https://github.com/tornadoweb/tornado/pull/3765","source":"security-advisories@github.com"},{"url":"https://github.com/tornadoweb/tornado/releases/tag/v6.6.0","source":"security-advisories@github.com"},{"url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-pcg2-g6cj-q92c","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-116577","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."}