# CVE-2025-69534: python3.13: Python-Markdown version 3.8 contain a vulnerability where malformed HTML-like sequences can cause html.parser.HTMLPar...

CVE-2025-69534 is fixed in 28 products on 1 platform, first by RHSA-2026:20677, released March 5, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-69534
- Priority: High
- CVSS: 8.2 (high)
- EPSS: 0.0066
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 5, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | idle-python3.10 Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [idle-python3.10 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-idle-python3.10-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | idle-python3.12 Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [idle-python3.12 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-idle-python3.12-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | libpython3.10 Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [libpython3.10 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libpython3.10-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | libpython3.10-minimal Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [libpython3.10-minimal 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libpython3.10-minimal-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | libpython3.10-stdlib Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [libpython3.10-stdlib 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libpython3.10-stdlib-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | libpython3.10-testsuite Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [libpython3.10-testsuite 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libpython3.10-testsuite-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | libpython3.12-minimal Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [libpython3.12-minimal 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libpython3.12-minimal-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | libpython3.12-stdlib Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [libpython3.12-stdlib 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libpython3.12-stdlib-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | libpython3.12-testsuite Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [libpython3.12-testsuite 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libpython3.12-testsuite-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | libpython3.12t64 Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [libpython3.12t64 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libpython3.12t64-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | pypy3 Debian 14 | 8.0.0+dfsg-1 | [DEBIAN-CVE-2025-69534](https://patchblox.com/security/data/fix/linux/debian-cve-2025-69534.md) | Mar 5, 2026 |
| Linux | python-Markdown opensuse-leap 15.6 | 3.5.2-150600.3.3.1 | [SUSE-SU-2026:0846-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0846-1.md) | Mar 6, 2026 |
| Linux | python-markdown RHEL 10 | 3.5.1-6.el10_0.1 | [RHSA-2026:20677](https://patchblox.com/security/data/fix/linux/rhsa-2026-20677.md) | Mar 5, 2026 |
| Linux | python-markdown rocky 10 | 0:3.5.1-6.el10_2.1 | [RLSA-2026:19155](https://patchblox.com/security/data/fix/linux/rlsa-2026-19155.md) | May 29, 2026 |
| Linux | python-markdown rocky 9 | 0:3.3.4-4.el9_8.2 | [RLSA-2026:19366](https://patchblox.com/security/data/fix/linux/rlsa-2026-19366.md) | May 28, 2026 |
| Linux | python3-markdown RHEL 9 | 0:3.3.4-4.el9_8.2 | [RHSA-2026:19366](https://patchblox.com/security/data/fix/linux/rhsa-2026-19366.md) | May 27, 2026 |
| Linux | python3-markdown almalinux 10 | 3.5.1-6.el10_2.1 | [ALSA-2026:19155](https://patchblox.com/security/data/fix/linux/alsa-2026-19155.md) | May 19, 2026 |
| Linux | python3-markdown almalinux 9 | 3.3.4-4.el9_8.2 | [ALSA-2026:19366](https://patchblox.com/security/data/fix/linux/alsa-2026-19366.md) | May 19, 2026 |
| Linux | python3-markdown amzn 2023 | 3.3.4-2.amzn2023.0.4 | [ALAS2023-2026-1492](https://patchblox.com/security/data/fix/linux/alas2023-2026-1492.md) | Mar 16, 2026 |
| Linux | python3-markdown ol 10 | 0:3.5.1-6.el10_2.1 | [ELSA-2026-19155](https://patchblox.com/security/data/fix/linux/elsa-2026-19155.md) | Jul 16, 2026 |
| Linux | python3-markdown ol 9 | 0:3.3.4-4.el9_8.2 | [ELSA-2026-19366](https://patchblox.com/security/data/fix/linux/elsa-2026-19366.md) | Jun 23, 2026 |
| Linux | python3.10 Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [python3.10 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3.10-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | python3.10-examples Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [python3.10-examples 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3.10-examples-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | python3.10-full Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [python3.10-full 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3.10-full-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | python3.10-minimal Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [python3.10-minimal 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3.10-minimal-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | python3.10-nopie Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [python3.10-nopie 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3.10-nopie-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | python3.10-venv Ubuntu 22.04.1 LTS (jammy) | 3.10.12-1~22.04.16 | [python3.10-venv 3.10.12-1~22.04.16](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3.10-venv-3.10.12-1-22.04.16.md) | Jul 7, 2026 |
| Linux | python3.11 Debian 12.15 (bookworm) | 3.11.2-6+deb12u9 | [DEBIAN-CVE-2025-69534](https://patchblox.com/security/data/fix/linux/debian-cve-2025-69534.md) | Mar 5, 2026 |
| Linux | python3.12 Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [python3.12 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3.12-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | python3.12-examples Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [python3.12-examples 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3.12-examples-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | python3.12-full Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [python3.12-full 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3.12-full-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | python3.12-minimal Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [python3.12-minimal 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3.12-minimal-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | python3.12-nopie Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [python3.12-nopie 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3.12-nopie-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | python3.12-venv Ubuntu 24.04.5 LTS (noble) | 3.12.3-1ubuntu0.15 | [python3.12-venv 3.12.3-1ubuntu0.15](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3.12-venv-3.12.3-1ubuntu0.15.md) | Jul 7, 2026 |
| Linux | python3.13 Debian 13.5 (trixie) | 3.13.4-1 | [DEBIAN-CVE-2025-69534](https://patchblox.com/security/data/fix/linux/debian-cve-2025-69534.md) | Mar 5, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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