EUVD-2025-17498
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
3Description
Deserialization of Untrusted Data vulnerability in themeton FLAP - Business WordPress Theme allows Object Injection. This issue affects FLAP - Business WordPress Theme: from n/a through 1.5.
Analysis
Critical deserialization vulnerability in themeton FLAP - Business WordPress Theme (versions up to 1.5) that allows unauthenticated remote attackers to achieve arbitrary object injection without user interaction. The vulnerability has a near-perfect CVSS score of 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating complete compromise of confidentiality, integrity, and availability is possible. Given the network-accessible attack vector and low complexity, this represents a critical risk to all WordPress installations using vulnerable theme versions.
Technical Context
This vulnerability stems from CWE-502 (Deserialization of Untrusted Data), a known critical weakness in PHP object deserialization. The FLAP Business Theme likely implements insecure unserialize() calls or similar unsafe deserialization functions on user-controlled input without proper validation. WordPress themes commonly accept serialized data through POST parameters, AJAX endpoints, or plugin hooks without sanitization. An attacker can craft a malicious serialized PHP object that, when unserialized by the vulnerable theme, triggers object injection chains leveraging PHP's magic methods (__wakeup, __destruct, __toString) or gadget chains from installed WordPress plugins/libraries. This allows Remote Code Execution (RCE) on the WordPress host without authentication or user interaction.
Affected Products
Vendor: themeton; Product: FLAP - Business WordPress Theme; Affected Versions: 1.5 and earlier (description indicates 'from n/a through 1.5', suggesting all versions up to and including 1.5); Likely CPE: cpe:2.3:a:themeton:flap_business_wordpress_theme:*:*:*:*:*:wordpress:*:*. All WordPress installations using this theme in versions 1.5 or lower across any PHP version and WordPress version are affected. The vulnerability affects the theme itself, independent of WordPress core patching status.
Remediation
Immediate actions: (1) Update FLAP - Business WordPress Theme to version 1.5.1 or later if available from themeton (verify through official WordPress.org theme repository or vendor site); (2) If no patch is available, immediately disable and deactivate the vulnerable theme, switching to an alternative WordPress theme; (3) As a temporary mitigation if patching is delayed, implement Web Application Firewall (WAF) rules to block common serialization attack patterns (strings containing 'O:' or 'C:' followed by length indicators); (4) Review WordPress access logs for suspicious unserialize() activity or POST requests with URL-encoded serialized data; (5) Scan the WordPress installation and web host for evidence of compromise (backdoors, modified files, unauthorized admin accounts). Contact themeton directly for patch timeline confirmation. Apply patches to all WordPress instances running this theme immediately upon availability.
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External POC / Exploit Code
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