What is CVE-2026-21629?

CVE-2026-21629 is a high-severity vulnerability in Joomla Joomla\!, classified under Improper Access Control. CVSS score: 7.3/10. Published 2026-04-01.

How severe is CVE-2026-21629?

High severity. CVSS v3 base score is 7.3 out of 10.

Vulnerability in Joomla Joomla\!

CVE-2026-21629

The ajax component was excluded from the default logged-in-user check in the administrative area. This behavior was potentially unexpected by 3rd party developers.

Published 2026-04-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.002 (14.6th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 14.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Joomla Joomla\!
Joomla! Project Cms — versions 3.0.0-5.4.3, 6.0.0-6.0.3

Weakness classification (CWE)

CWE-284 — Improper Access Control

References

developer.joomla.org/security-centre/1027-20260301-core-acl-hardening-in-com-aj… (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-21629?: CVE-2026-21629 is a high-severity vulnerability in Joomla Joomla\!, classified under Improper Access Control. CVSS score: 7.3/10. Published 2026-04-01.
How severe is CVE-2026-21629?: High severity. CVSS v3 base score is 7.3 out of 10.