CVE-2025-49869 Overview
CVE-2025-49869 is a PHP Object Injection vulnerability in the Arraytics Eventin (wp-event-solution) plugin for WordPress. The flaw originates from deserialization of untrusted data [CWE-502] and affects all plugin versions up to and including 4.0.31. Authenticated attackers with low privileges can submit crafted serialized payloads that the plugin unserializes, instantiating arbitrary PHP objects. When combined with a suitable gadget chain present in WordPress core or other installed plugins, this can lead to remote code execution, data tampering, or full site compromise.
Critical Impact
A low-privileged attacker can trigger object injection over the network to compromise confidentiality, integrity, and availability of the WordPress site.
Affected Products
- Arraytics Eventin (wp-event-solution) plugin for WordPress
- All versions from initial release through 4.0.31
- WordPress sites with the Eventin plugin installed and active
Discovery Timeline
- 2025-08-14 - CVE-2025-49869 published to the National Vulnerability Database
- 2026-04-23 - Last updated in the NVD database
Technical Details for CVE-2025-49869
Vulnerability Analysis
The Eventin plugin passes attacker-controlled input to a PHP deserialization routine such as unserialize() without validating the source or contents of the serialized data. When PHP deserializes the payload, it reconstructs objects and invokes magic methods including __wakeup(), __destruct(), and __toString(). An attacker who supplies a serialized object whose class is defined elsewhere in the WordPress runtime can hijack these magic method invocations to execute arbitrary logic.
The vulnerability is exploitable over the network and requires only low-privilege authentication, which on many WordPress deployments equates to a subscriber-level account. No user interaction is required to trigger the unserialize call once the malicious request is sent.
The Patchstack advisory classifies the issue as PHP Object Injection. Refer to the Patchstack Vulnerability Report for vendor-confirmed technical details.
Root Cause
The root cause is unsafe deserialization of user-supplied input. The plugin accepts serialized PHP data from an authenticated request context and passes it directly to unserialize() without using safe alternatives such as json_decode() or restricting allowed classes via the allowed_classes option introduced in PHP 7.
Attack Vector
An attacker authenticates to the target WordPress instance with any account that has access to the vulnerable Eventin endpoint. The attacker then sends a POST request containing a serialized PHP payload crafted to chain magic methods of available classes. Exploitation can yield arbitrary file writes, option modification, or code execution depending on the gadget chain available in the target environment.
Verified exploit code is not publicly available at the time of writing. The vulnerability mechanism is documented in the linked Patchstack advisory.
Detection Methods for CVE-2025-49869
Indicators of Compromise
- Inbound HTTP POST requests to Eventin plugin endpoints containing serialized PHP markers such as O:, a:, or s: followed by class names
- Unexpected creation or modification of PHP files under wp-content/ after authenticated requests to Eventin
- New or modified WordPress users, options, or scheduled tasks that correlate with Eventin endpoint access
- Outbound network connections initiated by the PHP worker process following Eventin requests
Detection Strategies
- Inspect WordPress access logs for requests to wp-event-solution REST routes and admin-ajax handlers containing serialized payload signatures
- Enable WordPress debug logging and monitor PHP error logs for unserialize() notices referencing undefined classes
- Deploy a Web Application Firewall ruleset that flags PHP serialized object syntax in request bodies and query parameters
Monitoring Recommendations
- Continuously monitor file integrity for the wp-content/plugins/wp-event-solution/ directory and core WordPress files
- Alert on creation of low-privilege accounts followed by requests to Eventin endpoints
- Track outbound DNS and HTTP traffic from the web server to detect post-exploitation command-and-control activity
How to Mitigate CVE-2025-49869
Immediate Actions Required
- Update the Arraytics Eventin plugin to a version released after 4.0.31 that addresses CVE-2025-49869
- Audit all WordPress user accounts and revoke unused or low-trust accounts that could be abused for authenticated exploitation
- Review the WordPress installation for unauthorized files, plugins, users, and scheduled tasks created since August 2025
Patch Information
Consult the Patchstack Vulnerability Report for the fixed plugin version and vendor remediation guidance. Apply the update through the WordPress plugin manager or by replacing the plugin directory with the patched release.
Workarounds
- Deactivate and remove the Eventin plugin until a patched version can be applied
- Restrict access to WordPress registration and the Eventin REST endpoints via web server access control lists or a WAF
- Enforce strong authentication and multi-factor authentication for all WordPress accounts to reduce the population of accounts capable of triggering the vulnerable code path
- Configure a WAF rule to block request bodies containing PHP serialized object patterns targeting Eventin routes
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
