Description
A flaw was found in libxml2 with Python bindings enabled. A remote attacker could exploit this vulnerability by providing a specially crafted XML document containing a Document Type Definition (DTD) with enumerated attribute values. This triggers a double-free error in the SAX attributeDecl callback handler, where a string is freed twice. This flaw can lead to a denial of service (DoS) due to a reproducible crash in Python applications using the libxml2 SAX bindings.
References10
- access.redhat.com/errata/RHSA-2026:64463
- access.redhat.com/errata/RHSA-2026:71585
- access.redhat.com/errata/RHSA-2026:71586
- access.redhat.com/errata/RHSA-2026:71641
- access.redhat.com/errata/RHSA-2026:72470
- access.redhat.com/errata/RHSA-2026:72475
- access.redhat.com/errata/RHSA-2026:72476
- access.redhat.com/errata/RHSA-2026:79357
- access.redhat.com/errata/RHSA-2026:82939
- access.redhat.com/errata/RHSA-2026:89750
Metrics
- CVSS 3.1
-
8.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 52 · as of 3 November 2026
- CWE
- CWE-763
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.