League/commonmark: Denial Of Service Via Colliding Heading Slugs

Impact "UniqueSlugNormalizer::normalize" makes each slug document-unique by searching for an unused numeric suffix, but restarts that search from "1" on every collision. The k-th heading that collapses to the same base slug performs k−1 array lookups, so K colliding slugs cost Σk−1 = OK². An...

DEBIAN-CVE-2026-86434

league/commonmark versions = 2.0.0 and 2.8.4 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its numeric-suffix search from 1 on every slug collision, resulting in OK^2 time complexity for K headings that collapse to the same base slug...

CVE-2026-86434

league/commonmark versions = 2.0.0 and 2.8.4 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its numeric-suffix search from 1 on every slug collision, resulting in OK^2 time complexity for K headings that collapse to the same base slug...

CVE-2026-86434 commonmark 2.0.0 through 2.8.3 Denial of Service via Slug Collision

league/commonmark versions = 2.0.0 and 2.8.4 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its numeric-suffix search from 1 on every slug collision, resulting in OK^2 time complexity for K headings that collapse to the same base slug...

CVE-2026-86434

league/commonmark versions = 2.0.0 and 2.9.0 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its numeric-suffix search from 1 on every slug collision, resulting in OK^2 time complexity for K headings that collapse to the same base slug...

CVE-2026-86434 commonmark 2.0.0 through 2.8.3 Denial of Service via Slug Collision

league/commonmark versions = 2.0.0 and 2.8.4 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its numeric-suffix search from 1 on every slug collision, resulting in OK^2 time complexity for K headings that collapse to the same base slug...

CVE-2026-86434 commonmark 2.0.0 through 2.8.3 Denial of Service via Slug Collision

league/commonmark versions = 2.0.0 and 2.8.4 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its numeric-suffix search from 1 on every slug collision, resulting in OK^2 time complexity for K headings that collapse to the same base slug...

CVE-2026-86434

league/commonmark (PHP) versions ≥ 2.0.0 and

PT-2026-86800

Name of the Vulnerable Software and Affected Versions league/commonmark versions 2.0.0 through 2.8.3 Description A denial of service issue exists in the UniqueSlugNormalizer::normalize function. The problem occurs when the function restarts its numeric-suffix search from 1 during every slug...

CVE-2026-86434: Inefficient Algorithmic Complexity

league/commonmark versions = 2.0.0 and 2.8.4 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its numeric-suffix search from 1 on every slug collision, resulting in OK^2 time complexity for K headings that collapse to the same base slug...

Linux Distros Unpatched Vulnerability : CVE-2026-86434

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - league/commonmark versions = 2.0.0 and 2.8.4 patched in 2.9.0 contain a denial of service vulnerability in UniqueSlugNormalizer::normalize, which restarts its...

PT-2026-75988

Impact UniqueSlugNormalizer::normalize makes each slug document-unique by searching for an unused numeric suffix, but restarts that search from 1 on every collision. The k-th heading that collapses to the same base slug performs k−1 array lookups, so K colliding slugs cost Σk−1 = OK². An attacker...