CVE-2026-92231: Joomla! Core - [20260915] - Core - XSS filter bypass in InputFilter via HTML5 entity decode mismatch in Joomla 1.5.0-5.4.8, 6.0.0-6.1.3

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-29 · updated 2026-10-06
Weakness: CWE-79

Description

Joomla! Core - [20260915] - Core - XSS filter bypass in InputFilter via HTML5 entity decode mismatch in Joomla 1.5.0-5.4.8, 6.0.0-6.1.3 - The checkAttribute method normalized an attribute value before testing it against the "javascript:" scheme regex, however without decoding HTML5 entities beforehand, causing an XSS vector.

Affected products

Joomla!: from 1.5.0 before 5.4.8; from 6.0.0 before 6.1.3 — fixed in 5.4.8, 6.1.3

How to fix

Upgrade to a fixed version: Joomla! 5.4.8, 6.1.3. Check the vendor advisory for mitigations.

References

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