What’s Vulnerable › Vulnerabilities

CVE-2025-12084: Quadratic complexity in node ID cache clearing

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-03 · updated 2026-06-17
• Weakness: CWE-407

Description

When building nested elements using xml.dom.minidom methods such as appendChild() that have a dependency on _clear_id_cache() the algorithm is quadratic. Availability can be impacted when building excessively nested documents.

Affected products

• Python: before 3.13.11; from 3.14.0 before 3.14.2; 3.15.0-alpha1, 3.15.0-alpha2 — fixed in 3.13.11, 3.14.2

How to fix

Upgrade to a fixed version: Python 3.13.11, 3.14.2. Check the vendor advisory for mitigations.

References

• https://github.com/python/cpython/commit/027f21e417b26eed4505ac2db101a4352b7c51a0
• https://github.com/python/cpython/commit/08d8e18ad81cd45bc4a27d6da478b51ea49486e4
• https://github.com/python/cpython/commit/27648a1818749ef44c420afe6173af6868715437
• https://github.com/python/cpython/commit/41f468786762348960486c166833a218a0a436af
• https://github.com/python/cpython/commit/57937a8e5e293f0dcba5115f7b7a11b1e0c9a273
• https://github.com/python/cpython/commit/8d2d7bb2e754f8649a68ce4116271a4932f76907
• https://github.com/python/cpython/commit/9c9dda6625a2a90d2a06c657eee021d6be19842d
• https://github.com/python/cpython/commit/a46c10ec9d4050ab67b8a932e0859a2ea60c3cb8
• https://github.com/python/cpython/commit/a696ba8b4d42fd632afc9bc88ad830a2e4cceed8
• https://github.com/python/cpython/commit/c97e87593063d84a2bd9fe7068b30eb44de23dc0
• https://github.com/python/cpython/commit/ddcd2acd85d891a53e281c773b3093f9db953964
• https://github.com/python/cpython/commit/e91c11449cad34bac3ea55ee09ca557691d92b53

Get alerted when CVE-2025-12084 or the next vulnerability affects your stack