CVE-2026-4224
Stack overflow parsing XML with deeply nested DTD content models
- State
- Published
- Severity
- 6.0 Medium
- Published
- Mar 16, 2026
- Updated
- Aug 13, 2026
- Reserved
- Mar 15, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.0 Medium | 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 | PSF |
Weaknesses
- CWE-674 Uncontrolled Recursion
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768patch
- https://mail.python.org/archives/list/security-announce@python.org/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/vendor-advisory
- https://github.com/python/cpython/issues/145986issue-tracking
- https://github.com/python/cpython/pull/145987patch
- https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4apatch
- https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3patch
- https://github.com/python/cpython/commit/642865ddf4b232da1f3b1f7abcfa3254c4bfe785patch
- https://github.com/python/cpython/commit/af856a7177326ac25d9f66cc6dd28b554d914feepatch
- https://github.com/python/cpython/commit/24ce88b285f56ee11626cf5e472af3cd8cc7c621patch
- http://www.openwall.com/lists/oss-security/2026/03/16/4
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