CVE-2026-76781 Libxml2: libxml2: null pointer dereference parsing nextcatalog without catalog attribute
A local attacker can cause a denial of service by providing a crafted XML catalog with a missing attribute, crashing applications using libxml2.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-76781?
CVE-2026-76781 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 17 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
A flaw was found in libxml2. A local user or an attacker providing a specially crafted XML catalog can trigger a NULL pointer dereference during XML catalog parsing. This occurs when a `nextCatalog` element lacks its mandatory `catalog` attribute, leading to the application crashing and causing a Denial of Service (DoS).
Weakness: CWE-476
Which versions are affected by CVE-2026-76781?
Linux distribution packages (5)
libxml2 Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.3.hum1 |
libxml2-16 Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.3.hum1 |
libxml2-devel Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.3.hum1 |
libxml2-static Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.3.hum1 |
python3-libxml2 Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.3.hum1 |
How do I fix CVE-2026-76781?
Apply the vendor's patch.
Is CVE-2026-76781 being exploited?
There is no known exploitation of CVE-2026-76781 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-76781, DEBIAN-CVE-2026-76781, ECHO-2007-775f-9d2b, GHSA-2j5r-8qjf-mq34, MGASA-2026-0558, RHSA-2026:57604 and 1 more.