What is CVE-2021-26036?

CVE-2021-26036 is a high-severity vulnerability in Joomla Joomla\!, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2021-07-07.

How severe is CVE-2021-26036?

High severity. CVSS v3 base score is 7.5 out of 10.

Improper input validation in Joomla Joomla\!

CVE-2021-26036

An issue was discovered in Joomla! 2.5.0 through 3.9.27. Missing validation of input could lead to a broken usergroups table.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2021-07-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.012 (67.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 67.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Joomla Joomla\!
Joomla! Project Cms — versions 2.5.0-3.9.27

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

developer.joomla.org/security-centre/857-20210702-core-dos-through-usergroup-ta… (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2021-26036?: CVE-2021-26036 is a high-severity vulnerability in Joomla Joomla\!, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2021-07-07.
How severe is CVE-2021-26036?: High severity. CVSS v3 base score is 7.5 out of 10.