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Fencer Vulns
medium 5.5

CVE-2026-76781 json

Libxml2: libxml2: null pointer dereference parsing nextcatalog without catalog attribute

published 2026-09-17 53 d ago modified 2026-11-06 3 d ago also EUVD-2026-81679

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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).

Patch / fix

  • Red Hat Red Hat Hardened Images 2.15.3-0.1.3.hum1
  • libxml2 Debian 14 2.15.4+dfsg-1

debian advisories DEBIAN-CVE-2026-76781

  • libxml2 Ubuntu 22.04 LTS 2.9.13+dfsg-1ubuntu0.14
  • libxml2 Ubuntu 24.04 LTS 2.9.14+dfsg-1.3ubuntu3.10
  • libxml2 Ubuntu 26.04 LTS 2.15.2+dfsg-0.1ubuntu0.3
  • libxml2 Ubuntu Pro 14.04 LTS 2.9.1+dfsg1-3ubuntu4.13+esm13
  • libxml2 Ubuntu Pro 16.04 LTS 2.9.3+dfsg1-1ubuntu0.7+esm14
  • libxml2 Ubuntu Pro 18.04 LTS 2.9.4+dfsg1-6.1ubuntu1.9+esm9
  • libxml2 Ubuntu Pro 20.04 LTS 2.9.10+dfsg-5ubuntu0.20.04.10+esm6

ubuntu advisories UBUNTU-CVE-2026-76781

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libxml2 hummingbird 1 2.15.3-0.1.3.hum1
  • libxml2-16 hummingbird 1 2.15.3-0.1.3.hum1
  • python3-libxml2 hummingbird 1 2.15.3-0.1.3.hum1

red hat advisories RHSA-2026:57604

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-76781 updated cvss 5.5

libxml2: libxml2: NULL pointer dereference parsing nextCatalog without catalog attribute

  • Red Hat Enterprise Linux 6 libxml2, libxml2-python Red Hat Enterprise Linux 7 libxml2, libxml2-python
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 podman, libxml2, podman-tests, podman-docker, podman-remote, podman-gvproxy, +4 more Red Hat Enterprise Linux 9 podman, podman-tests, podman-docker, podman-remote, podman-gvproxy, podman-plugins, +1 more Red Hat Enterprise Linux 10 podman Red Hat OpenShift Container Platform 4 podman, podman-tests, podman-docker, podman-remote, podman-gvproxy, podman-plugins, +4 more Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images libxml2 2.15.3-0.1.3.hum1, libxml2-16 2.15.3-0.1.3.hum1, python3-libxml2 2.15.3-0.1.3.hum1
    fixed: vendor fix RHSA-2026:57604
  • Red Hat Enterprise Linux 9 libxml2, python3-libxml2 Red Hat Enterprise Linux 10 libxml2 Red Hat Hardened Images swift-lang
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
53 d ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Container Platform 5

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.