EUVD-2026-77314
GHSA-2722-5gxq-8j64
Severity by source
CVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:N/AU:N/R:X/V:X/RE:X/U:X
Requires admin credentials (PR:H); a victim must load an affected page (UI:R); XSS fires in victim's browser context, constituting a scope change (S:C) with limited C/I impact.
Primary rating from Vendor (Joomla).
CVSS VectorVendor: Joomla
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Stored cross-site scripting in Quick Index (Free/Pro) extension for Joomla allows a privileged attacker to inject persistent script payloads by supplying a crafted class configuration value that breaks out of its HTML attribute context. Because Quick Index generates executable HTML output after Joomla's built-in content security filter has already processed plugin syntax, the platform's native XSS protection cannot intercept the injected payload. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires an authenticated Joomla administrator account (PR:H) with access to configure the Quick Index extension's class option in the backend. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (PR:H, AT:P, score 7.5) accurately captures the core constraint: exploitation is gated on prior possession of Joomla administrator credentials, which substantially limits the exposed population. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade Quick Index to version 5.0.5 or later, which addresses the missing HTML attribute encoding in the class option rendering path. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, complete an inventory of all Joomla installations to identify whether the Quick Index extension (Free or Pro) is installed and determine the exact version number currently deployed. …
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Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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