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.
CVE-2025-69534
This high-severity CVE scores 7.5 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 40% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 42.9%
- KEV
- Not listed
Published
March 5, 2026
Last Modified
June 30, 2026
Advisory Details (10)
Auto-updated Jul 2, 2026oss-security - CVE-2025-69534 in Python-Markdown
http://www.openwall.com/lists/oss-security/2026/03/06/4Security: CVE-2025-69534 – Remote DoS via malformed <![ sequence in Python-Markdown 3.8 · Issue #1534 · Python-Markdown/markdown · GitHub
https://github.com/Python-Markdown/markdown/issues/1534Bump version to 3.8.1 · Python-Markdown/markdown@3870f20 · GitHub
https://github.com/Python-Markdown/markdown/actions/runs/15736122892GitHub - Python-Markdown/markdown: A Python implementation of John Gruber’s Markdown with Extension support. · GitHub
https://github.com/Python-Markdown/markdownVendor Advisories for CVE-2025-69534(14)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:20676Red Hat Product SecurityHigh
Red Hat Security Advisory: python-markdown security update
- RHSA-2026:20674Red Hat Product SecurityHigh
Red Hat Security Advisory: python-markdown security update
- RHSA-2026:20677Red Hat Product SecurityHigh
Red Hat Security Advisory: python-markdown security update
- RHSA-2026:19366Red Hat Product SecurityHigh
Red Hat Security Advisory: python-markdown security update
- RHSA-2026:19155Red Hat Product SecurityHigh
Red Hat Security Advisory: python-markdown security update
- RHSA-2026:14874Red Hat Product SecurityHigh
Red Hat Security Advisory: Satellite 6.16.8 Async Update
- RHSA-2026:14873Red Hat Product SecurityHigh
Red Hat Security Advisory: Satellite 6.17.8 Async Update
- RHSA-2026:14835Red Hat Product SecurityHigh
Red Hat Security Advisory: Satellite 6.18.5 Async Update
- +6 more
Patch Availability(11)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | python-markdown-0:3.5.1-6.el10_0.1 | 2026-05-26 | redhat |
| redhat | python-markdown-0:3.3.4-4.el9_6.2 | 2026-05-26 | redhat |
| redhat | python-markdown-0:3.3.4-4.el9_4.2 | 2026-05-26 | redhat |
| redhat | python-markdown-0:3.3.4-4.el9_8.2 | 2026-05-19 | redhat |
| redhat | python-markdown-0:3.5.1-6.el10_2.1 | 2026-05-19 | redhat |
| redhat | python-markdown-0:3.8.2-1.el9pc | 2026-05-07 | redhat |
| redhat | python3.12-markdown-0:3.8.2-1.el9pc | 2026-05-07 | redhat |
| redhat | rhdh/rhdh-hub-rhel9:1777903262 | 2026-05-05 | redhat |
| redhat | python3.12-markdown-0:3.10.2-1.el9ap | 2026-05-04 | redhat |
| redhat | rhoai/odh-training-rocm62-torch25-py311-rhel9:1776272253 | 2026-04-23 | redhat |
| redhat | rhdh/rhdh-hub-rhel9:1776784286 | 2026-04-22 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| markdown | 1.7 ... 3.8 (54 versions) | — | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 60× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 04:31 UTCNVD updateseverity → HIGH
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 08:02 UTCOSV refresh
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-24 14:05 UTCEPSS rescore
- 2026-06-24 14:04 UTCEPSS rescore
- 2026-06-23 21:32 UTCEPSS rescore
- 2026-06-22 14:25 UTCEPSS rescore
- 2026-06-22 14:25 UTCEPSS rescore
Show 40 moreShow fewer
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 01:59 UTCEPSS rescore
- 2026-06-21 01:59 UTCEPSS rescore
- 2026-06-19 19:25 UTCEPSS rescore
- 2026-06-19 19:25 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-17 17:53 UTCEPSS rescore
- 2026-06-16 17:52 UTCEPSS rescore
- 2026-06-15 17:48 UTCEPSS rescore
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-06-12 00:40 UTCEG score recompute
- 2026-06-12 00:40 UTCVendor advisory
- 2026-06-11 14:00 UTCEPSS rescore
- 2026-06-10 22:18 UTCEPSS rescore
- 2026-06-10 18:51 UTCEG score recompute
- 2026-06-10 18:51 UTCVendor advisory
- 2026-06-10 13:22 UTCEPSS rescore
- 2026-06-10 06:26 UTCEG score recompute
- 2026-06-10 06:26 UTCVendor advisory
- 2026-06-09 17:43 UTCEG score recompute
- 2026-06-09 17:43 UTCVendor advisory
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 03:15 UTCEG score recompute
- 2026-06-08 03:15 UTCVendor advisory
- 2026-06-07 15:31 UTCEG score recompute
- 2026-06-07 15:31 UTCVendor advisory
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 00:53 UTCEG score recompute
- 2026-06-06 00:53 UTCVendor advisory
- 2026-06-06 00:53 UTCOSV refresh
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Frequently asked(5)
What is CVE-2025-69534?
When was CVE-2025-69534 disclosed?
Is CVE-2025-69534 actively exploited?
What is the CVSS score of CVE-2025-69534?
How do I remediate CVE-2025-69534?
Dependency Blast Radius
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