What is CVE-2026-6653?

CVE-2026-6653 is a critical-severity vulnerability in GNOME Libxml2, classified under Use After Free. CVSS score: 9.8/10. Published 2026-06-22.

How severe is CVE-2026-6653?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Use After Free in GNOME Libxml2

CVE-2026-6653

Use After Free in libxml2's xmlParseInternalSubset from GNOME libxml2 version 2.9.11 to 2.11.0 allows a remote attacker to cause a denial-of-service via maliciously crafted XML input with improper entity resolution handling.

Vulnerability class: Use-After-Free

Published 2026-06-22 · last modified 2026-07-14.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (26.7th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.004 · change: -0.002

Affected products

GNOME Libxml2 — versions 2.9.11
Xmlsoft Libxml2

Weakness classification (CWE)

References

bugs.launchpad.net/ubuntu/+source/libxml2/+bug/2141260 (issue-tracking, Exploit, Third Party Advisory, Issue Tracking)
gitlab.gnome.org/GNOME/libxml2/-/work_items/1058 (issue-tracking, Exploit, Patch, Issue Tracking)

Frequently asked questions

What is CVE-2026-6653?: CVE-2026-6653 is a critical-severity vulnerability in GNOME Libxml2, classified under Use After Free. CVSS score: 9.8/10. Published 2026-06-22.
How severe is CVE-2026-6653?: Critical severity. CVSS v3 base score is 9.8 out of 10.