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 chains with PHP Object Injection, allowing attackers to trigger unsafe deserialization through forged authenticated requests. The vulnerability affects all plugin versions up to and including 1.59. The issue is classified under [CWE-352] for missing CSRF protections and enables high-impact compromise of confidentiality, integrity, and availability when an authenticated user is tricked into clicking a malicious link.

Critical Impact
Successful exploitation lets a remote attacker chain CSRF with Object Injection to execute arbitrary PHP object operations, potentially leading to 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 installed and an authenticated administrator session

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 plugin exposes state-changing actions without validating a WordPress nonce or verifying request origin. An attacker who lures an authenticated user to a crafted page can submit forged requests to plugin endpoints. Because user-controlled input reaches a PHP deserialization sink, the CSRF flaw escalates into an Object Injection condition.

Object Injection arises when untrusted data is passed to unserialize() without validation. Attackers craft serialized payloads referencing classes available in the runtime, abusing magic methods such as __wakeup, __destruct, or __toString to trigger property-oriented programming chains. The combined CSRF and deserialization weakness allows high-impact compromise without prior privileges, requiring only user interaction.

Root Cause

The root cause is the absence of CSRF protection on plugin handlers that ultimately call PHP deserialization on attacker-influenced data. The plugin does not validate nonces using wp_verify_nonce() or check capabilities before processing requests, and it does not sanitize serialized input before passing it to deserialization routines.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker hosts a malicious page containing an auto-submitting form or image tag that issues a request to the vulnerable plugin endpoint. When a logged-in WordPress user visits the page, the browser forwards authentication cookies and the forged request executes server-side. The serialized payload then triggers Object Injection during processing. See the Patchstack CSRF Vulnerability Advisory for advisory details.

Detection Methods for CVE-2025-53277

Indicators of Compromise

Unexpected POST or GET requests to IS-theme-companion plugin endpoints originating from external Referer headers
Presence of serialized PHP payload patterns such as O: or a: in plugin request parameters
New or modified WordPress administrator accounts, plugins, or theme files following suspicious request activity
Outbound connections from the web server process to unfamiliar hosts after plugin interaction

Detection Strategies

Inspect web server access logs for cross-origin requests to plugin handlers without valid WordPress nonce parameters
Deploy a web application firewall rule to flag serialized PHP object patterns in HTTP parameters targeting the plugin
Monitor WordPress audit logs for option changes, user creation, or file modifications correlated with external referrers

Monitoring Recommendations

Enable file integrity monitoring on wp-content/plugins/weblizar-companion/ and the WordPress core directories
Correlate authentication events with administrative configuration changes to surface CSRF-driven actions
Alert on PHP errors referencing unserialize() failures or unknown class instantiation in web server logs

How to Mitigate CVE-2025-53277

Immediate Actions Required

Update IS-theme-companion to a version later than 1.59 once the vendor publishes a fix
Deactivate and remove the plugin if no patched release is available and the functionality is non-essential
Force administrators to log out of active WordPress sessions and rotate credentials after deactivation
Review the site for unauthorized administrator accounts, modified files, and scheduled tasks

Patch Information

No confirmed patched version is referenced in the NVD entry at the time of publication. Monitor the Patchstack CSRF Vulnerability Advisory and the WordPress plugin repository for vendor updates beyond version 1.59.

Workarounds

Restrict access to /wp-admin/ by IP allowlist to reduce the pool of authenticated targets
Enforce SameSite=Strict or SameSite=Lax cookie attributes on WordPress session cookies to limit cross-origin submission
Deploy a WAF rule blocking requests containing serialized PHP object signatures targeting plugin paths
Require administrators to use isolated browser profiles when managing the WordPress site

bash

# Example WAF rule (ModSecurity) blocking serialized payloads to the plugin
SecRule REQUEST_URI "@contains /wp-admin/admin.php" \
  "chain,phase:2,deny,status:403,id:1005327,msg:'Possible PHP Object Injection via IS-theme-companion'"
  SecRule ARGS "@rx O:[0-9]+:\"[A-Za-z_]+\"" "t:none"