CVE-2026-23549: WpEvently Object Injection Vulnerability

CVE-2026-23549 Overview

CVE-2026-23549 is a critical Insecure Deserialization vulnerability affecting the WpEvently (mage-eventpress) WordPress plugin developed by magepeopleteam. The vulnerability allows unauthenticated attackers to inject malicious PHP objects through deserialization of untrusted data, potentially leading to remote code execution, data exfiltration, or complete site compromise.

Critical Impact

This PHP Object Injection vulnerability enables attackers to execute arbitrary code on vulnerable WordPress installations without authentication, potentially compromising the entire web server.

Affected Products

• WpEvently (mage-eventpress) versions through 5.1.1
• WordPress installations with the vulnerable plugin active
• Any web server hosting affected WordPress sites

Discovery Timeline

• 2026-02-19 - CVE-2026-23549 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-23549

Vulnerability Analysis

This vulnerability is classified as CWE-502 (Deserialization of Untrusted Data). The WpEvently plugin fails to properly validate and sanitize serialized data before passing it to PHP's unserialize() function. When user-controlled input is deserialized without adequate verification, attackers can craft malicious serialized objects that, upon deserialization, trigger dangerous operations through PHP's magic methods such as __wakeup(), __destruct(), or __toString().

The network-accessible attack vector combined with no authentication requirements makes this vulnerability particularly dangerous for publicly accessible WordPress sites. An attacker can exploit this remotely without any user interaction, making automated attacks highly feasible.

Root Cause

The root cause lies in the improper handling of serialized PHP data within the WpEvently plugin. The plugin accepts serialized input from untrusted sources and passes it directly to PHP's unserialize() function without implementing proper input validation, allowlisting of acceptable classes, or using safer alternatives like json_decode(). This architectural flaw enables PHP Object Injection attacks when combined with exploitable gadget chains present in WordPress core or other installed plugins.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. Attackers can exploit this vulnerability by sending specially crafted HTTP requests containing malicious serialized PHP objects to vulnerable endpoints exposed by the WpEvently plugin. Upon deserialization, these objects can trigger POP (Property-Oriented Programming) chains that leverage existing class destructors or magic methods to achieve arbitrary code execution.

The exploitation process typically involves:

1. Identifying a gadget chain within WordPress core or installed plugins
2. Crafting a malicious serialized PHP object payload
3. Sending the payload to the vulnerable WpEvently endpoint
4. The server deserializes the malicious object, triggering the gadget chain
5. Arbitrary code execution or other malicious actions occur on the server

For detailed technical information, refer to the Patchstack security advisory.

Detection Methods for CVE-2026-23549

Indicators of Compromise

• Unusual HTTP POST requests to WpEvently plugin endpoints containing serialized PHP data patterns (e.g., O: or a: prefixes)
• Unexpected PHP process spawning or command execution from web server processes
• Web server logs showing requests with encoded serialized object payloads targeting /wp-content/plugins/mage-eventpress/ paths
• Creation of suspicious files in web-accessible directories or temporary folders

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in HTTP request bodies
• Monitor web server access logs for POST requests containing base64-encoded or URL-encoded serialized data patterns
• Deploy file integrity monitoring on WordPress plugin directories to detect unauthorized modifications
• Utilize endpoint detection solutions to identify suspicious PHP process behavior and shell command execution

Monitoring Recommendations

• Enable verbose logging for WordPress and PHP to capture detailed request information
• Configure alerting for any new file creation within WordPress directories, especially in /wp-content/uploads/ and plugin folders
• Monitor outbound network connections from the web server for potential data exfiltration or reverse shell activity
• Regularly audit installed WordPress plugins and their versions against known vulnerability databases

How to Mitigate CVE-2026-23549

Immediate Actions Required

• Update WpEvently (mage-eventpress) plugin to the latest patched version immediately
• If an update is not available, consider temporarily deactivating the WpEvently plugin until a patch is released
• Review web server and WordPress logs for any signs of exploitation attempts
• Implement WAF rules to block serialized PHP object patterns at the network perimeter
• Conduct a security audit of the WordPress installation to identify any signs of compromise

Patch Information

A security update addressing this PHP Object Injection vulnerability should be obtained from the official WordPress plugin repository or directly from magepeopleteam. System administrators should update the WpEvently plugin to a version newer than 5.1.1 once available. For detailed patch information, consult the Patchstack vulnerability database.

Workarounds

• Temporarily disable the WpEvently plugin if immediate patching is not possible
• Implement WAF rules to block requests containing serialized PHP object patterns such as O:[0-9]+:" in request bodies
• Restrict access to WordPress admin and plugin endpoints using IP allowlisting where feasible
• Enable WordPress security hardening measures including disabling PHP execution in upload directories

# Apache .htaccess configuration to block serialized PHP objects
# Add to WordPress root .htaccess file
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_METHOD} POST
RewriteCond %{THE_REQUEST} mage-eventpress
RewriteCond %{REQUEST_BODY} (O:[0-9]+:|a:[0-9]+:)
RewriteRule .* - [F,L]
</IfModule>