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.

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

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Python Software Foundation CPython unaffected
Version Status Constraints
0 affected
< 3.15.0

No data.

No data.

No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a cve-icon cve-icon
https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3 cve-icon cve-icon
https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768 cve-icon cve-icon
https://github.com/python/cpython/issues/145986 cve-icon cve-icon
https://github.com/python/cpython/pull/145987 cve-icon cve-icon
https://mail.python.org/archives/list/security-announce@python.org/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/ cve-icon cve-icon
History

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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: PSF

Published:

Updated: 2026-03-16T18:21:11.567Z

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

Link: CVE-2026-4224

cve-icon Vulnrichment

Updated: 2026-03-16T18:19:38.658Z

cve-icon NVD

Status : Received

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

Modified: 2026-03-16T19:16:18.870

Link: CVE-2026-4224

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses