CVE-2026-25869: MiniGal Nano Path Traversal Vulnerability

CVE-2026-25869 Overview

MiniGal Nano versions 0.3.5 and prior contain a path traversal vulnerability in index.php via the dir parameter. The application appends user-controlled input to the photos directory and attempts to prevent traversal by removing dot-dot sequences, but this protection can be bypassed using crafted directory patterns. An attacker can exploit this behavior to cause the application to enumerate and display image files from unintended filesystem locations that are readable by the web server, resulting in unintended information disclosure.

Critical Impact

This path traversal vulnerability allows unauthenticated remote attackers to read arbitrary image files from the web server's filesystem, potentially exposing sensitive information stored in locations outside the intended photos directory.

Affected Products

• MiniGal Nano version 0.3.5
• MiniGal Nano versions prior to 0.3.5
• All MiniGal Nano installations using the vulnerable index.php file

Discovery Timeline

• February 11, 2026 - CVE CVE-2026-25869 published to NVD
• February 11, 2026 - Last updated in NVD database

Technical Details for CVE-2026-25869

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as path traversal or directory traversal. The core issue lies in MiniGal Nano's insufficient input validation of the dir parameter passed to index.php. While the application implements a defense mechanism that attempts to strip dot-dot (..) sequences from user input, this sanitization approach is fundamentally flawed and can be bypassed using specially crafted directory patterns.

The web application's design appends user-controlled input directly to a base photos directory path without adequate validation. When an attacker supplies a carefully constructed path that evades the dot-dot removal logic, they can traverse outside the intended directory structure and access image files stored elsewhere on the filesystem that the web server process has read permissions for.

Root Cause

The root cause of this vulnerability is the inadequate implementation of path traversal protection in the dir parameter handling code. The application relies on a blacklist approach that removes specific character sequences (dot-dot patterns) rather than implementing a proper whitelist validation or canonicalization of the input path. This type of security control is inherently weak because attackers can often find alternative encodings, nested patterns, or other bypass techniques that circumvent the simple string removal operation. Proper path validation should use canonicalization followed by verification that the resolved path remains within the allowed directory, rather than attempting to filter out known malicious patterns.

Attack Vector

The vulnerability is exploitable remotely over the network without requiring any authentication or user interaction. An attacker can craft a malicious HTTP request to index.php with a specially constructed dir parameter value designed to bypass the dot-dot sequence removal. By using crafted directory patterns that are not properly sanitized, the attacker can escape the photos directory and cause the application to enumerate and display image files from arbitrary filesystem locations accessible to the web server process. This could include configuration files with image-like extensions, backup images, or any other readable image files stored outside the intended gallery directory.

Detection Methods for CVE-2026-25869

Indicators of Compromise

• Unusual HTTP requests to index.php containing encoded or nested dot-dot sequences in the dir parameter
• Web server access logs showing requests attempting directory traversal patterns such as ....//, ..;/, URL-encoded variations, or other evasion techniques
• Application errors or unexpected file enumeration responses indicating access to filesystem paths outside the configured photos directory

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing path traversal patterns in query parameters
• Configure server-side logging to capture full request URIs and enable alerting on suspicious dir parameter values
• Deploy SentinelOne Singularity XDR to monitor web server processes for anomalous file access patterns outside expected directories
• Review web server access logs regularly for requests targeting index.php with unusual path patterns

Monitoring Recommendations

• Enable verbose logging on web servers hosting MiniGal Nano to capture complete request parameters
• Monitor filesystem access patterns from the web server process for read operations outside the designated photos directory
• Implement real-time alerting for any detected path traversal attempt patterns in incoming HTTP requests

How to Mitigate CVE-2026-25869

Immediate Actions Required

• Restrict access to MiniGal Nano installations from untrusted networks until a patch is available
• Implement web application firewall rules to block requests containing path traversal sequences in the dir parameter
• Review web server configurations to ensure the web server process has minimal filesystem permissions
• Consider disabling or removing MiniGal Nano installations that are not actively needed

Patch Information

As of the last update to this vulnerability record, no official patch has been released by the vendor. MiniGal Nano is a legacy project, and users should consult the SourceForge Project Page and the VulnCheck Security Advisory for the latest information on available fixes or workarounds.

Workarounds

• Deploy a web application firewall (WAF) configured to reject requests containing path traversal patterns including encoded variations
• Modify web server configuration to restrict the web server process to only access the specific photos directory using chroot, AppArmor, SELinux, or similar isolation mechanisms
• Implement URL rewriting rules at the web server level to validate and reject malicious dir parameter values before they reach the application
• Consider migrating to an actively maintained photo gallery application with proper security controls

# Example Apache .htaccess configuration to block path traversal attempts
RewriteEngine On
RewriteCond %{QUERY_STRING} (\.\./) [NC,OR]
RewriteCond %{QUERY_STRING} (\.\.\\) [NC,OR]
RewriteCond %{QUERY_STRING} (%2e%2e) [NC]
RewriteRule ^index\.php$ - [F,L]