{"id":"CVE-2026-59922","aliases":["GHSA-c8j7-8cv4-2xmq","PYSEC-2026-2210"],"url":"https://o3.security/vulnerability/CVE-2026-59922","summary":"Mistune plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert)","details":"Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each possible start position, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.","published":"2026-07-08T16:12:00.545Z","modified":"2026-08-12T03:51:15.188702775Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"mistune","fixedVersion":"3.3.0"}],"fix":{"url":"https://github.com/lepture/mistune/commit/96d0f57f8fe9eeb06bb4cff521962a27d7c402e7","label":"lepture/mistune@96d0f57"},"references":[{"type":"WEB","url":"https://github.com/lepture/mistune/releases/tag/v3.3.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59922.json"},{"type":"ADVISORY","url":"https://github.com/lepture/mistune/security/advisories/GHSA-c8j7-8cv4-2xmq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59922"},{"type":"FIX","url":"https://github.com/lepture/mistune/commit/96d0f57f8fe9eeb06bb4cff521962a27d7c402e7"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:15.188702775Z"}}