Medium, CVSS 5.5PyPIAmendedPublished
Python-Markdown has an Uncaught Exception
CVE-2025-69534 · GHSA-5wmx-573v-2qwq
- Affected
- PyPI markdown < 3.8.1
- Fixed in
- 3.8.1· Vendor fix available
- Issue
- 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.
Recommended action: Upgrade to 3.8.1 or later, then redeploy and verify.A vendor fix does not resolve your finding until you verify it in your own systems.