Vulnerability in Python Software Foundation Cpython
CVE-2025-6069
The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.
Vulnerability class: ReDoS (Regular Expression Denial of Service)
EPSS: 0.005 (38.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
Affected products
- Python Software Foundation Cpython — versions 3.10.0, 0, 3.14.0a1
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cna@python.org (issue-tracking)
- cna@python.org (patch)
- cna@python.org (patch)
- cna@python.org (patch)
- cna@python.org (patch)
- cna@python.org (vendor-advisory)
- cna@python.org (patch)
- cna@python.org (patch)
- cna@python.org (patch)
- cna@python.org (patch)
Frequently asked questions
- What is CVE-2025-6069?
- CVE-2025-6069 is a medium-severity vulnerability in Python Software Foundation Cpython, classified under Inefficient Regular Expression Complexity. CVSS score: 4.3/10. Published 2025-06-17.
- How severe is CVE-2025-6069?
- Medium severity. CVSS v3 base score is 4.3 out of 10.
- Is CVE-2025-6069 known to be exploited?
- 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.