CVE-2026-92422: Meow Gallery WordPress Plugin XSS Vulnerability

CVE-2026-92422 Overview

CVE-2026-92422 affects the Meow Gallery WordPress plugin in versions prior to 5.5.5. The plugin fails to sanitize a user-supplied value before concatenating it into a shortcode string. That string is then handed to the WordPress shortcode parser on a publicly reachable endpoint. Unauthenticated attackers can execute arbitrary registered shortcodes and disclose non-public gallery content. The weakness is classified under [CWE-345] Insufficient Verification of Data Authenticity.

Critical Impact
Remote unauthenticated attackers can trigger arbitrary registered shortcodes on affected sites and disclose gallery content that should remain private.

Affected Products

Meow Gallery WordPress plugin versions prior to 5.5.5
WordPress sites running the vulnerable plugin with public gallery endpoints exposed
Sites that register additional shortcodes reachable through the plugin's parsing path

Discovery Timeline

2026-09-20 - CVE-2026-92422 published to NVD
2026-09-21 - Last updated in NVD database

Technical Details for CVE-2026-92422

Vulnerability Analysis

The Meow Gallery plugin exposes a public endpoint that accepts user-controlled input. That input is concatenated directly into a shortcode template string. The resulting string is passed to the WordPress do_shortcode() parser without prior sanitization or validation. Because WordPress evaluates any registered shortcode encountered in the string, attackers can inject shortcode syntax to invoke handlers that were never intended to be reachable from the endpoint.

The practical impact depends on which shortcodes are registered on the target site. In default installations, the plugin's own gallery shortcodes can be abused to render non-public galleries. On sites with additional plugins or themes, the attacker's reach expands to any shortcode registered in the global shortcode table.

Root Cause

The root cause is missing input validation before string concatenation into a shortcode payload. The plugin trusts a request parameter as safe shortcode context. WordPress's shortcode parser treats bracketed tokens as executable directives, so injected [shortcode] syntax is dispatched to the corresponding handler. This is a data-authenticity failure: the plugin cannot distinguish attacker-supplied shortcode tokens from developer-authored ones.

Attack Vector

An unauthenticated attacker sends an HTTP request to the plugin's public endpoint. The request includes shortcode syntax embedded in the vulnerable parameter. The server concatenates the payload, invokes the shortcode parser, and returns rendered output. No authentication, user interaction, or elevated privileges are required. Refer to the WPScan Vulnerability Report for technical specifics of the exploitation path.

Detection Methods for CVE-2026-92422

Indicators of Compromise

HTTP requests to Meow Gallery endpoints containing bracketed shortcode syntax such as [gallery], [mgl_gallery], or other registered shortcode tags in request parameters
Web server access logs showing unauthenticated requests to the plugin endpoint with unusually long or structured query parameters
Unexpected rendering of gallery content that is marked private or restricted in WordPress

Detection Strategies

Inspect WordPress access logs for requests to plugin AJAX or REST endpoints containing %5B (URL-encoded [) or literal [ characters in parameter values
Deploy web application firewall rules that flag shortcode syntax in query strings targeting the Meow Gallery plugin path
Correlate anomalous 200-response bodies containing gallery HTML with requests from unauthenticated sessions

Monitoring Recommendations

Enable verbose logging on the WordPress instance and forward events to a centralized log platform for query and retention
Alert on repeated requests from a single source targeting plugin endpoints within short time windows
Track outbound content sizes from gallery endpoints to identify bulk disclosure of restricted images

How to Mitigate CVE-2026-92422

Immediate Actions Required

Upgrade the Meow Gallery plugin to version 5.5.5 or later on all WordPress installations
Audit registered shortcodes on the site and remove any that are no longer needed to reduce attack surface
Review access logs for prior exploitation attempts and validate that no restricted gallery content was disclosed

Patch Information

The vendor addressed the issue in Meow Gallery version 5.5.5. Update through the WordPress plugin dashboard or by replacing plugin files with the fixed release. See the WPScan Vulnerability Report for advisory details.

Workarounds

Restrict access to the vulnerable plugin endpoint at the web server or WAF layer until the update is applied
Temporarily deactivate the Meow Gallery plugin if immediate patching is not feasible
Apply input filtering rules that reject requests containing [ or ] characters in the affected parameter

bash

# Example WAF rule to block shortcode syntax in query parameters
SecRule ARGS "@rx \[[a-zA-Z0-9_\-]+" \
  "id:1092422,phase:2,deny,status:403,\
  msg:'Blocked shortcode injection attempt (CVE-2026-92422)'"