What is CVE-2026-23899?

CVE-2026-23899 is a high-severity vulnerability in Joomla Joomla\!, classified under Improper Access Control. CVSS score: 8.8/10. Published 2026-04-01.

How severe is CVE-2026-23899?

High severity. CVSS v3 base score is 8.8 out of 10.

Vulnerability in Joomla Joomla\!

CVE-2026-23899

An improper access check allows unauthorized access to webservice endpoints.

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

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (31.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 31.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Joomla Joomla\!
Joomla! Project Cms — versions 4.0.0-5.4.3, 6.0.0-6.0.3

Weakness classification (CWE)

CWE-284 — Improper Access Control

References

developer.joomla.org/security-centre/1032-20260306-core-improper-access-check-i… (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-23899?: CVE-2026-23899 is a high-severity vulnerability in Joomla Joomla\!, classified under Improper Access Control. CVSS score: 8.8/10. Published 2026-04-01.
How severe is CVE-2026-23899?: High severity. CVSS v3 base score is 8.8 out of 10.