{"id":"EM-20261103-1AYV","url":"https://cyber.eventmonitor.net/incident/EM-20261103-1AYV/","type":"cve","title":"Mistune Vulnerability (CVE-2026-121437)","subtitle":"CVE-2026-121437","subject":"CVE-2026-121437","status":"Developing","severity":"high","affected":[],"headline":null,"born":"2026-11-03T15:17:35.147Z","firstSignal":"2026-11-03T14:28:29.000Z","lastSignal":"2026-11-03T15:17:35.147Z","updated":"2026-11-04T14:43:58.877Z","revision":1,"life":[{"status":"Born","at":"2026-11-03T15:17:35.147Z","why":"second independent source: C6 NVD CVE API 2.0"},{"status":"Developing","at":"2026-11-03T15:17:35.147Z","why":"signals keep joining"}],"changeLog":[{"at":"2026-11-03T14:28:29.000Z","what":"First signal: C41 Red Hat Security Data"},{"at":"2026-11-03T15:17:35.147Z","what":"Born: second source, C6 NVD CVE API 2.0. Page EM-20261103-1AYV created."}],"stages":[{"name":"Disclosed","at":"2026-11-03T15:17:35.147Z","detail":"C6 NVD published"},{"name":"Scored","at":"2026-11-03T15:17:35.147Z","detail":"CVSS 8.7 · EPSS 0.6%"},{"name":"Exploited","at":null,"detail":"No exploitation reported"},{"name":"Advisories","at":null,"detail":"None yet"},{"name":"Vendor Response","at":"2026-11-03T14:28:29.000Z","detail":"C41 published"},{"name":"Resolved","at":null,"detail":"After 14 quiet days"}],"signals":[{"at":"2026-11-03T14:28:29.000Z","source":"C41","sourceName":"Red Hat Security Data","role":"Vendor","severity":3,"title":"Red Hat: CVE-2026-121437 (important)","text":"mistune: mistune: Denial of Service via quadratic-time emphasis delimiter processing","url":"https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-121437.json"},{"at":"2026-11-03T15:17:35.147Z","source":"C6","sourceName":"NVD CVE API 2.0","role":"Database","severity":3,"title":"CVE-2026-121437 (CVSS 8.7)","text":"Mistune from 3.3.0 before 3.3.4 contains a denial of service vulnerability that allows remote attackers to exhaust CPU through quadratic-time emphasis delimiter processing. Attackers can submit small markdown documents with repeated patterns like \"*a_b\" to trigger an O(n²) index-fixup loop, stalling workers for seconds.","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121437"}],"crowd":[],"reference":{"nvd":{"published":"2026-11-03T15:17:35.147","score":8.7,"severity":"HIGH","desc":"Mistune from 3.3.0 before 3.3.4 contains a denial of service vulnerability that allows remote attackers to exhaust CPU through quadratic-time emphasis delimiter processing. Attackers can submit small markdown documents with repeated patterns like \"*a_b\" to trigger an O(n²) index-fixup loop, stalling","product":"","seen":1793803438877},"kev":null,"epss":{"epss":0.00619,"pct":0.49777,"at":1793803438877},"p0":false},"mergedInto":null,"publisher":"Event Monitor Cyber"}