CVE-2026-81153 in Robo Gallery Plugin
Summary
by MITRE • 10/11/2026
The Robo Gallery WordPress plugin before 5.2.6 does not sanitise and escape some of its image settings before outputting them in a gallery page, allowing users with the Author role and above to perform Stored Cross-Site Scripting attacks that execute in the browser of any visitor viewing the gallery, including administrators, even where the unfiltered_html capability is disallowed such as on multisite.
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Analysis
by VulDB Data Team • 10/11/2026
The Robo Gallery WordPress plugin version 5.2.6 and earlier contains a critical security flaw related to improper input validation and output encoding mechanisms. This vulnerability stems from the application's failure to properly sanitize user-supplied data before storing it in the database, as well its subsequent failure to escape that same data when rendering it within HTML contexts on gallery pages. Specifically, image settings configured by users are processed without adequate filtering or escaping procedures, creating a direct pathway for malicious script injection. This architectural oversight allows attackers who possess elevated privileges within the WordPress environment to inject executable JavaScript code into the application's output stream.
The operational impact of this vulnerability is significant due to its classification as a Stored Cross-Site Scripting attack. Unlike reflected XSS attacks that require tricking a user into clicking a malicious link, stored vulnerabilities persist on the server side by saving the malicious payload in the database or file system. Consequently, every time an administrator or any other visitor views the compromised gallery page, their browser automatically executes the injected script without further interaction from the attacker. This persistence ensures widespread exposure to all users accessing the affected content, effectively turning a standard media display feature into a vector for persistent compromise of client-side sessions and data integrity.
The severity of this issue is amplified by its ability to bypass specific WordPress security restrictions regarding unfiltered HTML capabilities. In many multi-site installations or hardened environments, administrators restrict certain user roles from using raw HTML tags to prevent code injection. However, because the vulnerability exploits a lack of escaping in image settings rather than direct content editor fields where such filters typically apply, it remains effective even when the unfiltered_html capability is explicitly disabled for authors and contributors. This means that users with relatively low privilege levels, specifically those holding the Author role or higher, can successfully execute these attacks without needing administrative-level permissions to bypass standard security controls.
From a technical classification perspective, this vulnerability aligns closely with CWE-79, which defines Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. The specific mechanism involves both insufficient sanitization at the input stage and inadequate escaping at the output stage, allowing malicious payloads to survive the data lifecycle within the application. In terms of offensive security frameworks such as MITRE ATT&CK for Enterprise or ICS, this behavior corresponds to techniques involving Client-Side Injection and potentially Account Manipulation if the script is used to steal session cookies or perform actions on behalf of authenticated users like administrators.
Mitigation strategies must focus on immediate remediation through software updates and enhanced configuration practices. The primary defense is upgrading the Robo Gallery plugin to version 5.2.6 or later, where these sanitization and escaping mechanisms have been corrected by the developers. For organizations unable to update immediately due to compatibility constraints, temporary mitigations include restricting access to gallery management features to only those users with absolute trust and highest privilege levels, although this is less effective given that authors can still exploit the flaw. Additionally, implementing a Web Application Firewall may help detect and block common XSS payloads in HTTP requests targeting these specific endpoints, providing an additional layer of defense while permanent fixes are deployed.