CVE-2025-5804: Case Theme User LFI Vulnerability

CVE-2025-5804 Overview

CVE-2025-5804 is a PHP Local File Inclusion (LFI) vulnerability in the Case Themes case-theme-user WordPress plugin. The flaw stems from improper control of filename arguments used in PHP include or require statements [CWE-98]. Attackers can manipulate file path parameters to include arbitrary local files on the server. This can lead to disclosure of sensitive configuration data, source code, and in some scenarios, remote code execution through log poisoning or file upload chaining. The vulnerability affects all versions of Case Theme User from initial release through versions below 1.0.4.

Critical Impact

Successful exploitation allows attackers to read arbitrary server files and potentially execute PHP code, compromising the confidentiality, integrity, and availability of the affected WordPress site.

Affected Products

• Case Themes Case Theme User plugin for WordPress (case-theme-user)
• All versions prior to 1.0.4
• WordPress installations with the vulnerable plugin enabled

Discovery Timeline

• 2026-04-10 - CVE-2025-5804 published to NVD
• 2026-04-24 - Last updated in NVD database

Technical Details for CVE-2025-5804

Vulnerability Analysis

The Case Theme User plugin fails to properly sanitize user-supplied input passed to PHP file inclusion functions. When a parameter controlling a filename reaches include, include_once, require, or require_once without validation, the PHP interpreter loads and executes whatever file path the attacker specifies. This pattern is classified under [CWE-98], Improper Control of Filename for Include/Require Statement in PHP Program.

Attackers can request files outside the intended directory using path traversal sequences such as ../. Common targets include wp-config.php, system files like /etc/passwd, and PHP session files. If the attacker can write content to a known local path, for example by poisoning web server access logs or uploading benign-looking files, the inclusion mechanism converts file disclosure into code execution.

Root Cause

The plugin code constructs an inclusion path using attacker-controlled input without applying an allowlist of permitted filenames or stripping directory traversal characters. Missing input validation on the filename parameter is the direct root cause.

Attack Vector

The attack is delivered over the network through standard HTTP requests to the WordPress site. Exploitation requires user interaction and has high attack complexity, as the attacker must identify the vulnerable parameter and craft a path that resolves to a useful target file. No authentication is required.

The vulnerability mechanism is described in the Patchstack WordPress Vulnerability advisory. No public proof-of-concept code has been released at the time of this writing.

Detection Methods for CVE-2025-5804

Indicators of Compromise

• HTTP requests to plugin endpoints containing path traversal sequences such as ../, ..%2f, or encoded null bytes
• Web server access log entries referencing sensitive paths like wp-config.php, /etc/passwd, or /proc/self/environ
• Unexpected PHP errors in logs referencing failed include or require calls with attacker-controlled paths
• Outbound connections or new admin users created shortly after suspicious inclusion requests

Detection Strategies

• Inspect WordPress access logs for query parameters handled by the case-theme-user plugin containing file path syntax
• Deploy web application firewall rules that block path traversal patterns and known LFI payloads
• Audit installed plugin versions and flag any case-theme-user installation at version 1.0.4 or earlier

Monitoring Recommendations

• Enable PHP error logging and alert on failed to open stream warnings tied to include/require operations
• Monitor file integrity on wp-config.php and other sensitive configuration files
• Track read access to web server log files from the PHP-FPM or Apache process, which can indicate log poisoning attempts

How to Mitigate CVE-2025-5804

Immediate Actions Required

• Update the Case Theme User plugin to version 1.0.4 or later as soon as the vendor releases a fixed build
• Disable the case-theme-user plugin if a patched version is not yet available
• Review web server logs for prior exploitation attempts targeting plugin parameters

Patch Information

The vulnerability affects Case Theme User versions through < 1.0.4. Refer to the Patchstack WordPress Vulnerability advisory for the current vendor remediation status and upgrade guidance.

Workarounds

• Restrict access to the WordPress site behind a web application firewall that blocks directory traversal payloads
• Configure PHP open_basedir to confine file inclusion to the WordPress installation directory
• Apply least-privilege filesystem permissions so the web server user cannot read sensitive system files
• Disable allow_url_include in php.ini to prevent escalation from local file inclusion to remote file inclusion

# Example php.ini hardening
allow_url_include = Off
allow_url_fopen = Off
open_basedir = "/var/www/html:/tmp"