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

Low 3.7 Published 15 Jan 2026 Updated 1 Sep 2026

Attackers can cause application crashes via stack overflow by exploiting unbounded recursion in libxml2's RelaxNG parser when processing crafted schemas.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-0989?

CVE-2026-0989 is a low-severity denial of service vulnerability in Ibm Aix, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-674

Which versions are affected by CVE-2026-0989?

It affects 7 products.

Linux distribution packages (20)

`libxml2` SUSE:Linux Enterprise Micro 5.2	All versions	`2.9.7-150000.3.91.1`
`python-libxml2-python` SUSE:Linux Enterprise Micro 5.2	All versions	`2.9.7-150000.3.91.1`
`libxml2` SUSE:Linux Enterprise Micro 5.5	All versions	`2.10.3-150500.5.35.1`
`libxml2-python` SUSE:Linux Enterprise Micro 5.5	All versions	`2.10.3-150500.5.35.1`
`libxml2` SUSE:Linux Enterprise Server 16.0	All versions	`2.13.8-160000.3.1`
`libxml2-python` SUSE:Linux Enterprise Server 16.0	All versions	`2.13.8-160000.3.1`
`libxml2` SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5	All versions	`2.9.4-46.96.1`
`python-libxml2` SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5	All versions	`2.9.4-46.96.1`
`libxml2` SUSE:Linux Enterprise Server for SAP applications 16.0	All versions	`2.13.8-160000.3.1`
`libxml2-python` SUSE:Linux Enterprise Server for SAP applications 16.0	All versions	`2.13.8-160000.3.1`
`libxml2` SUSE:Linux Micro 6.0	All versions	`2.11.6-11.1`
`libxml2` SUSE:Linux Micro 6.1	All versions	`2.11.6-slfo.1.1_7.1`
`libxml2` SUSE:Linux Micro 6.2	All versions	`2.13.8-160000.3.1`
`libxml2-python` SUSE:Linux Micro 6.2	All versions	`2.13.8-160000.3.1`
`libxml2` openSUSE:Leap 15.6	All versions	`2.10.3-150500.5.35.1`
`libxml2-python` openSUSE:Leap 15.6	All versions	`2.10.3-150500.5.35.1`
`python-libxml2-python` openSUSE:Leap 15.6	All versions	`2.9.7-150000.3.91.1`
`libxml2` openSUSE:Leap 16.0	All versions	`2.13.8-160000.3.1`
`libxml2-python` openSUSE:Leap 16.0	All versions	`2.13.8-160000.3.1`
`libxml2` openSUSE:Tumbleweed	All versions	`2.14.5-2.1`

Products include Ibm Aix, Ibm Vios, Redhat Enterprise Linux, Redhat Hardened Images, Redhat Jboss Core Services, Redhat Openshift Container Platform and 1 more.

How do I fix CVE-2026-0989?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-0989 being exploited?

There is no known exploitation of CVE-2026-0989 in the wild and no public exploit code.

All Ibm Aix vulnerabilities

Sources

Also known as AZL-74775, AZL-74786, BELL-CVE-2026-0989, DEBIAN-CVE-2026-0989, ECHO-8419-807a-4b8d, GHSA-3xfm-x84x-qwwq and 11 more.