What is CVE-2019-12766?

CVE-2019-12766 is a medium-severity vulnerability in Joomla Joomla\!, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2019-06-11.

How severe is CVE-2019-12766?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Joomla Joomla\!

CVE-2019-12766

An issue was discovered in Joomla! before 3.9.7. The subform fieldtype does not sufficiently filter or validate input of subfields. This leads to XSS attack vectors.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2019-06-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.009 (58.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 58.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Joomla Joomla\!

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

developer.joomla.org/security-centre/784-20190602-core-xss-in-subform-field (Vendor Advisory)
www.securityfocus.com/bid/108735 (VDB Entry, Third Party Advisory, vdb-entry, Broken Link)

Frequently asked questions

What is CVE-2019-12766?: CVE-2019-12766 is a medium-severity vulnerability in Joomla Joomla\!, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2019-06-11.
How severe is CVE-2019-12766?: Medium severity. CVSS v3 base score is 6.1 out of 10.