VulnerabilityModified
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.
MEDIUM 6.0EPSS 0.69%
Does this matter?
Lower severity and a low EPSS score (0.69%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 6.0 MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.69% probability · 51th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-674
- Affected
- python/python
- Source
- cna@python.org
References
- https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4aPatch
- https://github.com/python/cpython/commit/24ce88b285f56ee11626cf5e472af3cd8cc7c621
- 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/issues/145986Issue Tracking
- https://github.com/python/cpython/pull/145987Patch
- https://mail.python.org/archives/list/security-announce@python.org/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/03/16/4Mailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.