{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "3.3.0"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "15c3b79325125272263d7d42492ec8f757447191"
            },
            {
              "fixed": "2b04d7ba341c16ac78fe82d3076bdd5c3de87c69"
            }
          ],
          "repo": "https://github.com/lepture/mistune",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-ffq3-xpv3-j92q"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1333",
      "CWE-407"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59928.json"
  },
  "details": "Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune/block_parser.py and the ref_links environment dictionary handling, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.",
  "id": "CVE-2026-59928",
  "modified": "2026-08-12T03:51:41.300968623Z",
  "published": "2026-07-08T16:23:21Z",
  "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-2026-59928.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/lepture/mistune/security/advisories/GHSA-ffq3-xpv3-j92q"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59928"
    },
    {
      "type": "FIX",
      "url": "https://github.com/lepture/mistune/commit/2b04d7ba341c16ac78fe82d3076bdd5c3de87c69"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mistune block_parser: quadratic-time parsing on long lists of repeated reference-link definitions"
}