{"id":"CVE-2026-4224","title":"When an Expat parser with a registered ElementDeclHandler parses an inline\ndocument type definition containing a deeply nested content model a C stack\noverflow occurs.","summary":"When an Expat parser with a registered ElementDeclHandler parses an inline\ndocument type definition containing a deeply nested content model a C stack\noverflow occurs.","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-674","CWE-805"],"vendor":"python","product":"python","affected":["python < 3.10.0","python >= 3.13.0, < 3.13.13","python >= 3.14.0, < 3.14.4","python = 3.15.0"],"patched":["python 3.14.4"],"published":"2026-03-16","updated":"2026-08-05","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-4224","references":[{"url":"https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/24ce88b285f56ee11626cf5e472af3cd8cc7c621","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/642865ddf4b232da1f3b1f7abcfa3254c4bfe785","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/af856a7177326ac25d9f66cc6dd28b554d914fee","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768","label":"cna@python.org"},{"url":"https://github.com/python/cpython/issues/145986","label":"cna@python.org"},{"url":"https://github.com/python/cpython/pull/145987","label":"cna@python.org"},{"url":"https://mail.python.org/archives/list/security-announce@python.org/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/","label":"cna@python.org"},{"url":"http://www.openwall.com/lists/oss-security/2026/03/16/4","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4224.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-4224"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2448181"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-4224"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4224"},{"url":"https://access.redhat.com/errata/RHSA-2026:19064"},{"url":"https://access.redhat.com/errata/RHSA-2026:19019"},{"url":"https://access.redhat.com/errata/RHSA-2026:10950"},{"url":"https://access.redhat.com/errata/RHSA-2026:19177"},{"url":"https://access.redhat.com/errata/RHSA-2026:19176"},{"url":"https://access.redhat.com/errata/RHSA-2026:8822"},{"url":"https://access.redhat.com/errata/RHSA-2026:8824"},{"url":"https://access.redhat.com/errata/RHSA-2026:7443"},{"url":"https://access.redhat.com/errata/RHSA-2026:7661"},{"url":"https://access.redhat.com/errata/RHSA-2026:21275"},{"url":"https://access.redhat.com/errata/RHSA-2026:58981"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.0069,"epssPercentile":0.50944,"ingestedAt":"2026-08-05T11:47:24.045Z","scores":{"nvd":7.5,"vendor":5.9},"slug":"CVE-2026-4224","body":"## Overview\n\nWhen an Expat parser with a registered ElementDeclHandler parses an inline\ndocument type definition containing a deeply nested content model a C stack\noverflow occurs.\n\n## Affected\n\n- `python < 3.10.0`\n- `python >= 3.13.0, < 3.13.13`\n- `python >= 3.14.0, < 3.14.4`\n- `python = 3.15.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `python 3.14.4`\n\n## Vendor advisories\n\n- **RHSA-2026:19064** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19064)\n- **RHSA-2026:19019** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19019)\n- **RHSA-2026:10950** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-04-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:10950)\n- **RHSA-2026:19177** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19177)\n- **RHSA-2026:19176** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19176)\n- **RHSA-2026:8822** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:8822)\n- **RHSA-2026:8824** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:8824)\n- **RHSA-2026:7443** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:7443)\n- **RHSA-2026:7661** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:7661)\n- **RHSA-2026:21275** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-05-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:21275)\n- **RHSA-2026:58981** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-08-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:58981)\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux AI (RHEL AI) 3 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-10 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4224.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}