SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-85190

Joomla Extension - regularlabs.com - Privileged stored XSS via class option in Quick Index extension for Joomla < 5.0.5 - Quick Index inserts configurable class values into generated HTML without escaping them for an HTML attribute.

HIGH 7.5EPSS 0.42%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.42%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Joomla Extension - regularlabs.com - Privileged stored XSS via class option in Quick Index extension for Joomla < 5.0.5 - Quick Index inserts configurable class values into generated HTML without escaping them for an HTML attribute. A crafted value can close the intended class attribute and introduce a new attribute. Joomla's content filter cannot reliably prevent this because Quick Index creates the executable HTML after the authored plugin syntax was filtered.

CVSS 4.0
7.5 HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.42% probability · 36th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-79
Source
security@joomla.org
EPSS trend
0%3%5%26 October 2026: 0.42%26 October 202626 October 2026

EPSS 0.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.