CVE-2026-4224

HIGH

Stack overflow parsing XML with deeply nested DTD content models

Title source: cna
STIX 2.1

Description

When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs.

References (9)

Core 9
Core References
Issue Tracking issue-tracking
https://github.com/python/cpython/issues/145986

Scores

CVSS v3 7.5
EPSS 0.0062
EPSS Percentile 44.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-674
Status published
Products (6)
python/python 3.15.0 alpha1 (7 CPE variants)
python/python < 3.10.0
Python Software Foundation/CPython < 3.13.13
Python Software Foundation/CPython < 3.15.0
Python Software Foundation/CPython 3.14.0 - 3.14.4
Python Software Foundation/CPython 3.15.0a1 - 3.15.0a8
Published Mar 16, 2026
Tracked Since Mar 17, 2026