Vulnerability Report

CVE-2026-4224

Title: C stack overflow in Expat parser

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-4224.

CWE Category NVD-CWE-noinfo

Published Date Mar 16, 2026

Modified Date Jun 04, 2026

Exploit Status Not Found

Score 6.0 CVSS v4.0

Exploit Probability (EPSS)

0.62%

Vulnerability Summary

CVE-2026-4224: 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.

Impacted Vendors

python 1

python_software_foundation 1

Reference Links

https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3 https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768 https://github.com/python/cpython/issues/145986 https://github.com/python/cpython/pull/145987 https://mail.python.org/archives/list/[email protected]/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/

CVSS v4.0

Source Entity [email protected]

Severity MEDIUM

6.0

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

N/A

RAW 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.5