CVE-2026-4224
Published: March 17, 2026Last modified: August 25, 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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | python3 | Fixed (3.11.16-r0) |
| 25 LTS | python3 | Fixed (3.12.14-r0) | |
| Stream | python3 | Fixed (3.14.3-r1) | |
| Hardened Containers | 23 LTS | python3 | Fixed (3.11.16-r0) |
| 25 LTS | python3 | Fixed (3.12.14-r0) | |
| Stream | python3 | Fixed (3.14.3-r1) |
References
- http://www.openwall.com/lists/oss-security/2026/03/16/4
- https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a
- https://github.com/python/cpython/commit/24ce88b285f56ee11626cf5e472af3cd8cc7c621
- https://github.com/python/cpython/commit/642865ddf4b232da1f3b1f7abcfa3254c4bfe785
- https://github.com/python/cpython/commit/af856a7177326ac25d9f66cc6dd28b554d914fee
- 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://github.com/python/cpython/pull/145999
- https://github.com/python/cpython/pull/146000
- https://mail.python.org/archives/list/[email protected]/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/