CVE-2026-66146

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Cross-Site Scripting (XSS) in SonicWall GMS

Publication date: 2026-08-11

Last updated on: 2026-08-28

Assigner: SonicWALL, Inc.

Description

Multiple Cross-Site Scripting (XSS) vulnerabilities were identified in GMS 9.5.1 (Build 9510.1044) and earlier versions that allow a remote attacker to execute javascript script in a user's browser.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-11

Last Modified

2026-08-28

Generated

2026-09-01

AI Q&A

2026-08-12

EPSS Evaluated

2026-08-30

NVD

CVE-2026-66146

EUVD

EUVD-2026-56939

Affected Vendors & Products

Vendor	Product	Version / Range
sonicwall	gms	to 9.5.1 (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 vulnerability is a Cross-Site Scripting (XSS) flaw in SonicWall GMS versions 9.5.1 (Build 9510.1044) and earlier. It allows a remote attacker to inject malicious JavaScript code into a user's browser session.

Detection Guidance

This vulnerability involves Cross-Site Scripting (XSS) in SonicWall GMS versions 9.5.1 (Build 9510.1044) and earlier. Detection requires inspecting web application inputs for XSS payloads. Manually test input fields by injecting basic XSS vectors like <script>alert(1)</script> or <img src=x onerror=alert(1)>. Use browser developer tools to monitor network requests and responses for suspicious script execution.

Impact Analysis

An attacker could exploit this to steal session cookies, redirect users to malicious sites, or perform actions on behalf of the user. It may lead to unauthorized data access or account compromise.

Compliance Impact

This XSS vulnerability could expose sensitive user data, violating GDPR's data protection requirements or HIPAA's safeguards for protected health information. Organizations may face compliance penalties if exploited.

Mitigation Strategies

Update GMS to version 9.5.1 (Build 9510.1044) or later to address the XSS vulnerabilities. Implement input validation and output encoding for user-supplied data. Use Content Security Policy (CSP) headers to mitigate XSS impact.

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