{
  "cveId": "CVE-2026-86434",
  "url": "https://patchblox.com/security/cve/CVE-2026-86434",
  "summary": "CVE-2026-86434 is fixed in php-league-commonmark on 1 platform by DEBIAN-CVE-2026-86434 (version 2.9.0-1), released September 8, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "php-league-commonmark: league/commonmark versions \u003E= 2.0.0 and \u003C 2.8.4 (patched in 2.9.0) contain a denial of service vulnerability in Uniqu...",
  "description": "league/commonmark versions \u003E= 2.0.0 and \u003C 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 O(K^2) time complexity for K headings that collapse to the same base slug. The vulnerable path is reached when HeadingPermalinkExtension, FootnoteExtension, or TableOfContentsExtension is registered. An unauthenticated attacker can force many headings onto a single base slug (e.g., via empty ATX headings, identical heading text, or punctuation-only headings) in a small Markdown document, consuming excessive CPU and denying service.",
  "published": "2026-09-07T13:20:42Z",
  "severity": "",
  "epss": 0.00509,
  "epssPercentile": 0.43744,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "php-league-commonmark",
      "release": "Debian 14",
      "fixedVersion": "2.9.0-1",
      "fix": "DEBIAN-CVE-2026-86434",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-86434",
      "released": "2026-09-08T02:27:47Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}