{"id":"CVE-2026-86433","title":"commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning","summary":"commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers…","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-407"],"vendor":"thephpleague","product":"commonmark","affected":["commonmark >= 1.5.0 < 2.8.4"],"published":"2026-09-07","updated":"2026-09-08","sourceUpdated":"2026-09-08T19:57:49.663","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-86433","references":[{"url":"https://github.com/thephpleague/commonmark/security/advisories/GHSA-g2gp-3wwq-f4ph","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-attributes","label":"disclosure@vulncheck.com"}],"tags":["nvd","cve.org"],"epss":0.00291,"epssPercentile":0.21957,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-08T12:50:12.374530Z"},"ingestedAt":"2026-09-08T15:33:26.977Z","slug":"CVE-2026-86433","body":"## Overview\n\ncommonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}