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mistune — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2026-76098

Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0 through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML rendering creates deeply nested emphasis tokens from consecutive asterisk characters, and recursive rendering in HTMLRenderer.render_token() can exceed Python's recursion limit and raise RecursionError, allowing crafted Markdown to crash a parsing process. This issue is fixed in version 3.3.3

Products
mistune
Affected versions
2.0.4-1, 2.0.4-2, 3.0.2-1, 3.0.2-2, 3.1.3-1, 3.1.4-1, 3.3.4-1
Fixed versions
Not specified
CVEs
CVE-2026-76098
Confirmed fixed CVEs
Not specified
Updated in this feed
30 Oct 2026, 09:03 UTC · Revision 1

Source evidence

DEBIAN-CVE-2026-76098

core-osv · Original source

Published 24 Aug 2026, 20:17 UTC

Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0 through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML rendering creates deeply nested emphasis tokens from consecutive asterisk characters, and recursive rendering in HTMLRenderer.render_token() can exceed Python's recursion limit and raise RecursionError, allowing crafted Markdown to crash a parsing process. This issue is fixed in version 3.3.3

osv:DEBIAN-CVE-2026-76098

mistune

Fixed versions: Not specified

mistune

Fixed versions: Not specified

mistune

Fixed versions: Not specified

Complete source record
{
  "id": "4c1b275e8b89f4bae8e5590959dc50dce211a43f431fdbb0a24c76fb7ce97eac",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-76098",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-76098",
    "summary": "Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0 through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML rendering creates deeply nested emphasis tokens from consecutive asterisk characters, and recursive rendering in HTMLRenderer.render_token() can exceed Python's recursion limit and raise RecursionError, allowing crafted Markdown to crash a parsing process. This issue is fixed in version 3.3.3",
    "evidence": "osv:DEBIAN-CVE-2026-76098",
    "products": [
      {
        "name": {
          "value": "mistune",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.0.4-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.0.4-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "3.0.2-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "3.0.2-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "3.1.3-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "3.1.4-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "3.3.4-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "mistune",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "3.1.3-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "3.1.4-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "3.3.4-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "mistune",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "3.1.3-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "3.1.4-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "3.3.4-1",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2026-76098",
      "aliases": [
        "DEBIAN-CVE-2026-76098"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "mistune",
            "purl": "pkg:deb/debian/mistune?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "2.0.4-1",
            "2.0.4-2",
            "3.0.2-1",
            "3.0.2-2",
            "3.1.3-1",
            "3.1.4-1",
            "3.3.4-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-76098.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "mistune",
            "purl": "pkg:deb/debian/mistune?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "3.1.3-1",
            "3.1.4-1",
            "3.3.4-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-76098.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "mistune",
            "purl": "pkg:deb/debian/mistune?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "3.1.3-1",
            "3.1.4-1",
            "3.3.4-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-76098.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-13T09:47:42.156628675Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-76098"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-76098"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-76098",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 307590,
  "published_at": "2026-08-24T20:17:19.33+00:00"
}