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HIGH

CVE-2025-69534

CVSS v3

7.5

HIGH

EPSS Score

0.6 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • markdownPyPIall versions · fixed in 3.8.1
  • python3-markdownAlmaLinux:10all versions · fixed in 3.5.1-6.el10_2.1
  • python3-markdownAlmaLinux:9all versions · fixed in 3.3.4-4.el9_8.2

Vendor advisories

  • CVE-2025-69534 Red Hat Product Security42 products fixed · 6 known affected

    python-markdown: denial of service via malformed HTML-like sequences

    ansible-automation-platform-26/controller-rhel9 as a component of Red Hat Ansible Automation Platform 2 · rhoai/odh-modelmesh-runtime-adapter-rhel8 as a component of Red Hat OpenShift AI (RHOAI) · rhoai/odh-training-cuda121-torch24-py311-rhel9 as a component of Red Hat OpenShift AI (RHOAI)

  • RHSA-2026:20676 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: python-markdown security update

  • RHSA-2026:20674 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: python-markdown security update

  • RHSA-2026:20677 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: python-markdown security update

  • RHSA-2026:19366 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: python-markdown security update

  • RHSA-2026:19155 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: python-markdown security update

8 more advisories

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-03-05
Last Modified
2026-03-13

Frequently asked questions

What is CVE-2025-69534?

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.

Is CVE-2025-69534 actively exploited?

Active exploitation of CVE-2025-69534 has not been confirmed. Its EPSS score was 0.6% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-69534?

CVE-2025-69534 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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