{"id":"CVE-2025-69534","title":"Python-Markdown version 3.8 contain a vulnerability where malformed HTML-like sequences can cause html.parser.HTMLParser to raise an unhandled AssertionError during Markdown parsing","summary":"Python-Markdown version 3.8 contain a vulnerability where malformed HTML-like sequences can cause html.parser.HTMLParser to raise an unhandled AssertionError during Markdown parsing. Because Python-Markdown does not catch this exception,…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-400","CWE-617"],"vendor":"python-markdown","product":"markdown","affected":["markdown = 3.8"],"published":"2026-03-05","updated":"2026-09-07","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-69534","references":[{"url":"https://github.com/Python-Markdown/markdown","label":"cve@mitre.org"},{"url":"https://github.com/Python-Markdown/markdown/actions/runs/15736122892","label":"cve@mitre.org"},{"url":"https://github.com/Python-Markdown/markdown/issues/1534","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2026/03/06/4","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2026:10184","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:13508","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:13512","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:13826","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:14835","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:14873","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:14874","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:19155","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:19366","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:20674","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:20676","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:20677","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:9742","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2025-69534","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2444839","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-69534.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-69534"},{"url":"https://github.com/Python-Markdown/markdown/pull/1535"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/markdown/PYSEC-2026-89.yaml"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-69534"}],"tags":["nvd","osv","pip","csaf","vex","red-hat"],"epss":0.00602,"epssPercentile":0.4857,"ingestedAt":"2026-09-07T14:12:11.009Z","aliases":["GHSA-5wmx-573v-2qwq","PYSEC-2026-89"],"ecosystem":"pip","patched":["markdown 3.8.1"],"scores":{"nvd":7.5,"vendor":8.2},"slug":"CVE-2025-69534","body":"## Overview\n\nPython-Markdown version 3.8 contain a vulnerability where malformed HTML-like sequences can cause html.parser.HTMLParser to raise an unhandled AssertionError during Markdown parsing. Because Python-Markdown does not catch this exception, any application that processes attacker-controlled Markdown may crash. This enables remote, unauthenticated Denial of Service in web applications, documentation systems, CI/CD pipelines, and any service that renders untrusted Markdown. The issue was acknowledged by the vendor and fixed in version 3.8.1. This issue causes a remote Denial of Service in any application parsing untrusted Markdown, and can lead to Information Disclosure through uncaught exceptions.\n\n## Affected\n\n- `markdown = 3.8`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2025-69534)\n\nAffected packages:\n\n- `markdown < 3.8.1`\n\nPatched in:\n\n- `markdown 3.8.1`\n\nSource: https://osv.dev/vulnerability/GHSA-5wmx-573v-2qwq\n\n## Vendor advisories\n\n- **RHSA-2026:13512** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.5 for RHEL 8, Red Hat Ansible Automation Platform 2.5 for RHEL 9 · released 2026-05-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:13512)\n- **RHSA-2026:14874** · Red Hat · fixed in: Red Hat Satellite 6.16 for RHEL 8, Red Hat Satellite 6.16 for RHEL 9 · released 2026-05-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:14874)\n- **RHSA-2026:13508** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.6 for RHEL 9 · released 2026-05-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:13508)\n- **RHSA-2026:14873** · Red Hat · fixed in: Red Hat Satellite 6.17 for RHEL 9 · released 2026-05-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:14873)\n- **RHSA-2026:14835** · Red Hat · fixed in: Red Hat Satellite 6.18 for RHEL 9 · released 2026-05-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:14835)\n- **RHSA-2026:20677** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20677)\n- **RHSA-2026:19155** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19155)\n- **RHSA-2026:20674** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS EUS (v.9.4) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20674)\n- **RHSA-2026:20676** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS EUS (v.9.6) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20676)\n- **RHSA-2026:19366** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19366)\n- **RHSA-2026:9742** · Red Hat · fixed in: Red Hat Developer Hub 1.8 · released 2026-04-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:9742)\n- **Red Hat VEX** · Important · affected: Red Hat Ansible Automation Platform 2, Red Hat OpenShift AI (RHOAI), Red Hat Satellite 6 · no fix planned: Red Hat OpenShift AI (RHOAI), Red Hat Ansible Automation Platform 2, Red Hat Satellite 6 · updated 2026-10-09 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-69534.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}