CVE-2026-0989: Libxml2: unbounded relaxng include recursion leading to stack overflow

Severity: low (CVSS 3.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-01-15 · updated 2026-09-01
Weakness: CWE-674

Description

A flaw was identified in the RelaxNG parser of libxml2 related to how external schema inclusions are handled. The parser does not enforce a limit on inclusion depth when resolving nested <include> directives. Specially crafted or overly complex schemas can cause excessive recursion during parsing. This may lead to stack exhaustion and application crashes, creating a denial-of-service risk.

Affected products

IBM AIX: from 7.2.5 before 7.2.5.12; from 7.3.2 before 7.3.3.3; 7.3.4 — fixed in 7.2.5.12, 7.3.3.3
IBM VIOS: from 4.1.0 before 4.1.1.30; 4.1.2.0 — fixed in 4.1.1.30
Red Hat Enterprise Linux: 6.0, 7.0, 8.0, 9.0, 10.0
RedHat Hardened Images: all versions
RedHat Jboss Core Services: all versions
Red Hat OpenShift Container Platform 4.18: 4.0
xmlsoft libxml2: before 2.15.2 — fixed in 2.15.2

How to fix

Upgrade to a fixed version: IBM AIX 7.2.5.12, 7.3.3.3; IBM VIOS 4.1.1.30; xmlsoft libxml2 2.15.2. Check the vendor advisory for mitigations.

References

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