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CVE-2026-4224

MEDIUMCVSS 6/10EPSS 0.62%

Last modified

CVE-2026-4224 is a medium-severity vulnerability rated 6/10 on the CVSS scale. 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.. EPSS estimates a 0.62% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 4.0
6/10

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

EPSS Probability
0.62%

45.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
PythonPython< 3.10.0—
PythonPython>= 3.13.0, < 3.13.13—
PythonPython>= 3.14.0, < 3.14.4—
PythonPython3.15.0Alpha1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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.
How severe is CVE-2026-4224?
CVE-2026-4224 has a CVSS score of 6/10 (MEDIUM severity). The EPSS model estimates a 0.62% probability of exploitation in the next 30 days.
How do I fix CVE-2026-4224?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-4224?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST