CVE-2026-4224
HIGHCVSS 7.5/10EPSS 0.64%
Last modified
CVE-2026-4224 is a high-severity vulnerability rated 7.5/10 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 0.64% 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
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Python | Python | < 3.10.0 | — |
| Python | Python | >= 3.13.0, < 3.13.13 | — |
| Python | Python | >= 3.14.0, < 3.14.4 | — |
| Python | Python | 3.15.0 | Alpha1 |
References
- https://github.com/python/cpython/issues/145986Issue Tracking
- https://www.openwall.com/lists/oss-security/2026/03/16/4Mailing List, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
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 7.5/10 (HIGH severity). The EPSS model estimates a 0.64% 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.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2026-4224?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST