CVE-2025-69534
Python-Markdown has an Uncaught Exception
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.
How to fix CVE-2025-69534
To remediate CVE-2025-69534, upgrade the affected package to a fixed version below.
- —no fix listed
- —no fix listed
- —no fix listed
- —upgrade to 3.13.4-1 or later
- —no fix listed
- —no fix listed
- —upgrade to 3.8.1 or later
Is CVE-2025-69534 being exploited?
Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.
Affected packages (7)
- from 0
- from 0
- from 0
- from 0, < 3.13.4-1
- from 0
- from 0, <= 3.8
- from 0, < 3.8.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P |
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |