CVE-2025-53277: Weblizar Companion CSRF Vulnerability

CVE-2025-53277 Overview

CVE-2025-53277 is a Cross-Site Request Forgery (CSRF) vulnerability in the Infigo Software IS-theme-companion (weblizar-companion) WordPress plugin. The flaw affects all versions up to and including 1.59. Successful exploitation chains CSRF with PHP Object Injection, allowing attackers to trigger deserialization of attacker-controlled data when an authenticated user visits a malicious page. The vulnerability is tracked under CWE-352 and carries network attack vector with required user interaction.

Critical Impact

An attacker who tricks an authenticated WordPress user into visiting a crafted page can trigger object injection leading to potential remote code execution, data tampering, or site takeover.

Affected Products

• Infigo Software IS-theme-companion (weblizar-companion) plugin for WordPress
• All versions from initial release through 1.59
• WordPress sites with the plugin active and authenticated users

Discovery Timeline

• 2025-06-27 - CVE-2025-53277 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-53277

Vulnerability Analysis

The vulnerability combines two weaknesses in the IS-theme-companion plugin. State-changing actions in the plugin lack CSRF nonce verification, and at least one of these actions passes user-controlled input into a PHP deserialization routine. The result is a CSRF-to-Object-Injection chain.

An attacker hosts a malicious page or embeds a forged request on a third-party site. When an authenticated WordPress user, typically an administrator, visits the page, the browser sends an authenticated request to the vulnerable plugin endpoint. The endpoint accepts the request because no nonce is validated, then unserializes attacker-supplied data.

The attack requires user interaction but no privileges on the attacker side. Impact spans confidentiality, integrity, and availability, since object injection in a WordPress context can be escalated to arbitrary code execution through PHP "POP" gadget chains present in WordPress core or other installed plugins.

Root Cause

The root cause is missing anti-CSRF token validation on plugin request handlers, combined with unsafe use of unserialize() on untrusted input. The plugin does not call wp_verify_nonce() or equivalent checks before processing state-changing requests, and accepted parameters are deserialized without type or signature validation.

Attack Vector

Exploitation requires the attacker to lure an authenticated WordPress user to a malicious URL. The forged request reaches a vulnerable plugin endpoint with the victim's session cookies. The endpoint deserializes attacker-controlled payload data, instantiating PHP objects whose magic methods (__wakeup, __destruct) execute attacker-defined logic. Public POP gadget chains for WordPress and common plugins make this exploitable in practice. See the Patchstack Vulnerability Report for technical details.

Detection Methods for CVE-2025-53277

Indicators of Compromise

• Unexpected POST requests to IS-theme-companion plugin endpoints originating from external Referer headers
• Serialized PHP payloads (strings beginning with O:, a:, or s:) in request bodies or query parameters
• New or modified WordPress administrator accounts, options, or theme files following plugin requests
• PHP error log entries referencing unserialize() or unknown class instantiation from the plugin path

Detection Strategies

• Inspect web server access logs for authenticated requests to weblizar-companion handlers with off-site Referer values
• Deploy WAF rules that flag serialized PHP object patterns in request parameters
• Audit WordPress wp_options, user tables, and uploads directory for unexpected modifications after plugin interactions

Monitoring Recommendations

• Forward WordPress, PHP-FPM, and web server logs to a centralized SIEM for correlation of CSRF-style request patterns
• Alert on changes to administrator accounts, plugin files, and theme files
• Track outbound connections from PHP processes that could indicate post-exploitation command-and-control

How to Mitigate CVE-2025-53277

Immediate Actions Required

• Disable or remove the IS-theme-companion plugin until a patched version above 1.59 is confirmed installed
• Force logout of all WordPress administrators and rotate their credentials and application passwords
• Review recent admin activity, installed plugins, and modified files for signs of compromise
• Restrict /wp-admin/ access by IP allowlist or HTTP authentication where feasible

Patch Information

No fixed version is identified in the available CVE record beyond the affected range of <= 1.59. Site operators should monitor the plugin vendor's release notes and the Patchstack Vulnerability Report for an updated release that introduces nonce verification and removes unsafe deserialization.

Workarounds

• Uninstall the IS-theme-companion plugin if no patched version is yet available
• Deploy a Web Application Firewall rule that blocks requests to plugin endpoints lacking a valid wp_nonce parameter
• Block requests containing serialized PHP object markers (O: followed by digits and a class name) targeting WordPress endpoints
• Enforce SameSite=Strict or SameSite=Lax session cookies to reduce cross-site request reach

# Example WAF rule (ModSecurity) blocking serialized PHP objects to the plugin path
SecRule REQUEST_URI "@contains /wp-content/plugins/weblizar-companion/" \
    "phase:2,chain,deny,status:403,id:1005327,log,msg:'CVE-2025-53277 CSRF/Object Injection attempt'"
    SecRule ARGS|REQUEST_BODY "@rx O:\d+:\"[A-Za-z_\\\\]+\"" "t:none"