CVE-2026-66490

Analyzed Analyzed - Analysis Complete

Stored XSS in Gridbox Joomla Extension via Comment Avatar

Publication date: 2026-07-29

Last updated on: 2026-08-05

Assigner: Joomla! Project

Description

Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-07-29

Last Modified

2026-08-05

Generated

2026-08-19

AI Q&A

2026-07-30

EPSS Evaluated

2026-08-18

NVD

CVE-2026-66490

Affected Vendors & Products

Vendor	Product	Version / Range
balbooa	gridbox	to 2.20.2 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

This is a stored cross-site scripting (XSS) vulnerability in the Joomla extension Gridbox versions before 2.20.2. It allows attackers to inject malicious scripts via a comment avatar, which are then stored and executed when other users view the page.

Detection Guidance

This vulnerability is a stored XSS issue in Joomla Extension Gridbox versions before 2.20.2. Detection requires checking the installed version of Gridbox and reviewing user comments for malicious scripts in avatar fields. No specific network commands are provided in the context.

Impact Analysis

An attacker could steal user sessions, redirect users to malicious sites, or perform actions on behalf of users. Users with administrative access are particularly at risk if the vulnerability is exploited.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's integrity and confidentiality principles. For HIPAA, it may risk protected health information exposure, leading to compliance failures.

Mitigation Strategies

Update Gridbox to version 2.20.2 or later to address the stored XSS vulnerability in comment avatars.

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