CVE-2026-49851: Mistune: Potential DoS via quadratic-time parsing in parse_link_text
Mistune is vulnerable to a CPU exhaustion DoS due to superlinear (approximately O(n²)) behavior in parse_link_text. A relatively small input consisting of repeated [ characters causes significant parsing slowdown.
References
- access.redhat.com/security/cve/CVE-2026-49851
- bugzilla.redhat.com/show_bug.cgi?id=2492304
- github.com/advisories/GHSA-qcq2-496w-v96p
- github.com/lepture/mistune/security/advisories/GHSA-qcq2-496w-v96p
- nvd.nist.gov/vuln/detail/CVE-2026-49851
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49851.json
Code Behaviors & Features
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