{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "3.2.1"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "067f90861088a496942f5eb43236135352b85d39"
            }
          ],
          "repo": "https://github.com/lepture/mistune",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-v87v-83h2-53w7"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44897.json"
  },
  "details": "Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening \u003chN\u003e tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character \" in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.",
  "id": "CVE-2026-44897",
  "modified": "2026-08-12T03:51:15.723930796Z",
  "published": "2026-05-26T20:40:42.290Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/lepture/mistune/releases/tag/v3.2.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44897.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44897"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mistune Heading ID Attribute Injection XSS"
}