--- 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: 0.00663 epssPercentile: 0.51833 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 --- ## Overview 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, 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. ## Affected - `markdown = 3.8` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Package advisory (CVE-2025-69534) Affected packages: - `markdown < 3.8.1` Patched in: - `markdown 3.8.1` Source: https://osv.dev/vulnerability/GHSA-5wmx-573v-2qwq ## Vendor advisories - **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) - **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) - **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) - **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) - **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) - **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) - **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) - **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) - **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) - **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) - **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) - **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)