CVE-2025-69099 Overview
A deserialization of untrusted data vulnerability has been identified in the fuelthemes North WordPress theme (north-wp). This vulnerability allows attackers to perform PHP Object Injection attacks, which can lead to arbitrary code execution, privilege escalation, or other malicious activities depending on available gadget chains within the WordPress installation.
Critical Impact
Attackers can exploit this PHP Object Injection vulnerability to inject malicious serialized objects, potentially leading to remote code execution, unauthorized data access, or complete site compromise.
Affected Products
- fuelthemes North WordPress Theme versions up to and including 5.7.5
- WordPress installations using the North theme (north-wp)
Discovery Timeline
- 2026-01-22 - CVE CVE-2025-69099 published to NVD
- 2026-01-22 - Last updated in NVD database
Technical Details for CVE-2025-69099
Vulnerability Analysis
This vulnerability is classified as CWE-502: Deserialization of Untrusted Data. The North WordPress theme fails to properly validate or sanitize serialized data before deserializing it, allowing attackers to supply crafted serialized objects that, when deserialized, can trigger dangerous operations through PHP magic methods.
PHP Object Injection vulnerabilities occur when user-controllable input is passed to PHP's unserialize() function without adequate validation. When deserialization occurs, PHP reconstructs the object and may automatically invoke magic methods such as __wakeup(), __destruct(), or __toString(). If the WordPress installation contains classes with exploitable implementations of these methods (known as "gadget chains"), an attacker can chain them together to achieve malicious outcomes.
Root Cause
The root cause is improper handling of serialized data within the North WordPress theme. The theme processes user-supplied serialized input through the unserialize() function without implementing sufficient input validation, type checking, or allowlisting of acceptable classes. This architectural flaw enables attackers to control the class types and property values of deserialized objects.
Attack Vector
An attacker can exploit this vulnerability by crafting a malicious serialized PHP object and submitting it through an input vector accepted by the North theme. The attack typically involves:
- Identifying an entry point where serialized data is accepted
- Discovering available gadget chains within WordPress core, the theme, or installed plugins
- Constructing a serialized payload that leverages these gadgets
- Submitting the payload to trigger deserialization and execute the gadget chain
The serialized payload manipulates object properties to control execution flow when PHP magic methods are invoked during or after deserialization. For detailed technical information about this vulnerability, see the Patchstack WordPress Vulnerability Database.
Detection Methods for CVE-2025-69099
Indicators of Compromise
- Presence of serialized PHP objects in HTTP request parameters, cookies, or POST data containing unexpected class names
- Log entries showing errors related to deserialization or unexpected object instantiation
- Unusual PHP process behavior or file system modifications following requests to theme-related endpoints
- Web application firewall alerts for serialized PHP payloads
Detection Strategies
- Deploy web application firewall rules to detect and block serialized PHP objects in user input, particularly those containing object markers (O:) followed by class names
- Monitor PHP error logs for deserialization-related warnings or exceptions
- Implement file integrity monitoring to detect unauthorized changes to theme files or WordPress core
- Review access logs for suspicious requests targeting North theme endpoints with encoded or obfuscated payloads
Monitoring Recommendations
- Enable verbose logging on WordPress installations to capture detailed request information
- Configure real-time alerting for any detection of serialized object patterns in incoming requests
- Regularly audit installed themes and plugins for known vulnerabilities using security scanning tools
- Monitor for new PHP files or modifications to existing files that could indicate successful exploitation
How to Mitigate CVE-2025-69099
Immediate Actions Required
- Update the North WordPress theme to a patched version when available from fuelthemes
- Implement web application firewall rules to block requests containing serialized PHP objects
- Review and audit all user input handling within the theme for deserialization operations
- Consider temporarily disabling the North theme if a patch is not yet available and risk is deemed critical
- Ensure WordPress core and all plugins are updated to reduce available gadget chains
Patch Information
Organizations should monitor the fuelthemes vendor channels and the Patchstack advisory for patch availability. The vulnerability affects North theme versions from unknown through 5.7.5. Upgrade to a version higher than 5.7.5 once released by the vendor.
Workarounds
- Deploy a web application firewall with rules specifically designed to detect and block PHP serialized object injection attempts
- Add custom input validation at the application level to reject or sanitize serialized data before it reaches the theme's deserialization logic
- Restrict access to vulnerable theme functionality through IP allowlisting or authentication requirements
- Consider using PHP's allowed_classes parameter with unserialize() at the code level if custom modifications are possible
# Example WAF rule for ModSecurity to block serialized PHP objects
SecRule REQUEST_BODY|ARGS "@rx O:[0-9]+:\"[a-zA-Z_][a-zA-Z0-9_]*\":" \
"id:100001,phase:2,deny,status:403,msg:'PHP Object Injection Attempt Detected'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
