CVE-2026-39510: Final Tiles Grid Auth Bypass Vulnerability

CVE-2026-39510 Overview

CVE-2026-39510 is an Authorization Bypass Through User-Controlled Key vulnerability affecting the WP Chill Image Photo Gallery Final Tiles Grid WordPress plugin (final-tiles-grid-gallery-lite). This vulnerability, classified as CWE-639 (Insecure Direct Object References - IDOR), allows attackers to exploit incorrectly configured access control security levels to access or manipulate resources belonging to other users.

The vulnerability enables unauthorized access by allowing user-controlled input to directly reference internal objects without proper authorization checks. This type of flaw can lead to unauthorized data access, modification, or deletion of gallery content managed by the plugin.

Critical Impact

Attackers can bypass authorization controls to access, modify, or delete gallery resources belonging to other users by manipulating object references in requests.

Affected Products

• Image Photo Gallery Final Tiles Grid versions up to and including 3.6.11
• WordPress installations using the final-tiles-grid-gallery-lite plugin
• WP Chill Image Photo Gallery Final Tiles Grid plugin (all versions through 3.6.11)

Discovery Timeline

• 2026-04-08 - CVE CVE-2026-39510 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2026-39510

Vulnerability Analysis

This Insecure Direct Object Reference (IDOR) vulnerability exists in the Image Photo Gallery Final Tiles Grid plugin due to improper validation of user-supplied object identifiers. The plugin fails to adequately verify that the requesting user has appropriate authorization to access or modify the requested gallery resources.

When users interact with gallery functionality, the plugin accepts user-controlled parameters that directly reference internal objects (such as gallery IDs or image identifiers). Without proper authorization checks, an attacker can manipulate these references to access galleries or images belonging to other users, effectively bypassing the intended access control mechanisms.

This type of vulnerability is particularly dangerous in multi-user WordPress environments where different users manage separate gallery content, as it breaks the isolation between user resources.

Root Cause

The root cause of this vulnerability is the absence of proper authorization validation when processing user-controlled object references. The plugin accepts identifiers from user input and uses them directly to retrieve or modify resources without verifying that the authenticated user has the necessary permissions to perform the requested operation on that specific resource.

This represents a fundamental access control design flaw where authentication (verifying who the user is) is not properly coupled with authorization (verifying what the user can access).

Attack Vector

An authenticated attacker can exploit this vulnerability by:

1. Identifying the parameter used to reference gallery objects (e.g., gallery ID, image ID)
2. Modifying this parameter to reference objects belonging to other users
3. Submitting the modified request to gain unauthorized access to those resources

The attack requires authentication to the WordPress site but does not require administrative privileges. Any user with access to the gallery plugin functionality could potentially exploit this vulnerability to access other users' gallery content.

For detailed technical information about the exploitation mechanism, refer to the Patchstack Vulnerability Advisory.

Detection Methods for CVE-2026-39510

Indicators of Compromise

• Unusual access patterns to gallery resources from authenticated users
• Multiple requests with incrementing or sequential object identifiers from a single session
• Access logs showing users retrieving or modifying gallery content they did not create
• Error messages or anomalous responses when users access galleries outside their ownership

Detection Strategies

• Monitor WordPress access logs for unusual patterns of gallery object access
• Implement Web Application Firewall (WAF) rules to detect parameter tampering attempts
• Review audit logs for cross-user gallery access that violates expected access patterns
• Deploy endpoint detection solutions to identify exploitation attempts targeting WordPress plugins

Monitoring Recommendations

• Enable detailed logging for the Final Tiles Grid plugin to track object access
• Configure alerts for bulk sequential ID enumeration attempts
• Monitor for authenticated users accessing resources outside their normal scope
• Implement anomaly detection for unusual gallery access patterns

How to Mitigate CVE-2026-39510

Immediate Actions Required

• Update the Image Photo Gallery Final Tiles Grid plugin to a patched version when available
• Audit existing gallery access logs for signs of exploitation
• Consider temporarily disabling the plugin if a patch is not yet available
• Implement additional authorization checks at the web server or WAF level

Patch Information

Check the official WordPress plugin repository and the Patchstack advisory for updated versions of the plugin that address this vulnerability. Versions newer than 3.6.11 should contain the necessary security fixes.

Workarounds

• Restrict plugin access to trusted administrators only until patched
• Implement server-side access controls to validate gallery ownership before processing requests
• Use a Web Application Firewall to add an additional layer of authorization checking
• Consider disabling the affected plugin functionality temporarily in high-risk environments

# WordPress CLI command to check plugin version
wp plugin list --name=final-tiles-grid-gallery-lite --fields=name,version,update_version

# Disable the plugin temporarily if needed
wp plugin deactivate final-tiles-grid-gallery-lite

# Update the plugin when a patch is available
wp plugin update final-tiles-grid-gallery-lite