CVE-2026-4224

HIGH severity · CVSS 7.5 · CWE-674

7.5CVSS HIGH

Summary

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.

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

Confidentiality impactNone

Integrity impactNone

Availability impactHigh

Exploit probability (EPSS)0%

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

Affected products we track (1)

Python

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Official patch: https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a ↗

Additional information

NVD record
https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4aPatch
https://github.com/python/cpython/commit/642865ddf4b232da1f3b1f7abcfa3254c4bfe785Patch
https://github.com/python/cpython/commit/af856a7177326ac25d9f66cc6dd28b554d914feePatch
https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3Patch
https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768Patch
https://github.com/python/cpython/pull/145987Patch
https://github.com/python/cpython/issues/145986
https://mail.python.org/archives/list/security-announce@python.org/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/Advisory