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.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact partial

Affected Vendors & Products

Vendors Products
Python
  • Cpython

No data.

No data.

References
Link Providers
http://www.openwall.com/lists/oss-security/2026/03/16/4 cve-icon
https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a cve-icon cve-icon cve-icon
https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3 cve-icon cve-icon cve-icon
https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768 cve-icon cve-icon cve-icon
https://github.com/python/cpython/issues/145986 cve-icon cve-icon cve-icon
https://github.com/python/cpython/pull/145987 cve-icon cve-icon cve-icon
https://mail.python.org/archives/list/[email protected]/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/ cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-4224 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-4224 cve-icon
History

Tue, 17 Mar 2026 10:00:00 +0000

Type Values Removed Values Added
First Time appeared Python
Python cpython
Vendors & Products Python
Python cpython

Tue, 17 Mar 2026 00:30:00 +0000

Type Values Removed Values Added
References

Tue, 17 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-805
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Mon, 16 Mar 2026 19:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-674
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Mon, 16 Mar 2026 18:15:00 +0000

Type Values Removed Values Added
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.
Title Stack overflow parsing XML with deeply nested DTD content models
References
Metrics cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}
cve-icon MITRE

Status: PUBLISHED

Assigner: PSF

Published: 2026-03-16T17:52:26.639Z

Updated: 2026-03-16T23:08:21.692Z

Reserved: 2026-03-15T18:10:54.886Z

Link: CVE-2026-4224

cve-icon Vulnrichment

Updated: 2026-03-16T23:08:21.692Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-16T18:16:10.070

Modified: 2026-03-17T14:20:01.670

Link: CVE-2026-4224

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-16T17:52:26Z

Links: CVE-2026-4224 - Bugzilla