CVE-2025-57919: ConveyThis Object Injection Vulnerability

CVE-2025-57919 Overview

CVE-2025-57919 is a deserialization of untrusted data vulnerability in the ConveyThis conveythis-translate WordPress plugin. The flaw allows PHP Object Injection in all versions up to and including 269.1. Authenticated attackers with high privileges can inject arbitrary PHP objects into the application's deserialization flow. Successful exploitation can lead to remote code execution, data tampering, and full compromise of the affected WordPress site. The vulnerability is tracked under CWE-502: Deserialization of Untrusted Data.

Critical Impact
Object injection through unsafe deserialization can lead to arbitrary code execution, sensitive data exposure, and complete loss of site integrity on affected WordPress installations.

Affected Products

ConveyThis conveythis-translate WordPress plugin versions up to and including 269.1
WordPress sites running the Language Translate Widget for WordPress – ConveyThis plugin
Installations exposing privileged user accounts that interact with the vulnerable code path

Discovery Timeline

2025-09-22 - CVE-2025-57919 published to NVD
2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-57919

Vulnerability Analysis

The vulnerability stems from the plugin processing serialized PHP data from an untrusted source without validation. When PHP's unserialize() function operates on attacker-controlled input, it instantiates arbitrary classes available in the application scope. Object injection abuses PHP magic methods such as __wakeup, __destruct, and __toString to trigger unintended logic during deserialization. Attackers chain these methods through existing classes to build POP (Property-Oriented Programming) gadgets. The impact ranges from arbitrary file operations to remote command execution, depending on the gadgets present in WordPress core, themes, and other active plugins.

Root Cause

The plugin deserializes input received through plugin endpoints without first verifying its origin, integrity, or structure. The codebase relies on PHP's native serialization format rather than safer alternatives such as JSON with strict schema validation. According to the Patchstack CVE Analysis, the issue is classified as PHP Object Injection affecting all versions through 269.1.

Attack Vector

Exploitation requires network access to the WordPress site and an authenticated session with high privileges. An attacker submits a crafted serialized payload to the vulnerable endpoint. The plugin deserializes the payload, instantiating attacker-chosen classes and invoking their magic methods. With a suitable gadget chain, the attacker achieves arbitrary code execution within the PHP process. See the Patchstack advisory for additional technical context.

Detection Methods for CVE-2025-57919

Indicators of Compromise

Unexpected outbound connections originating from the PHP-FPM or web server process after plugin requests
New or modified PHP files in wp-content/plugins/, wp-content/uploads/, or theme directories
Web server access logs containing serialized PHP markers such as O: or a: in POST bodies or query strings to plugin endpoints
Unexplained WordPress administrator account creation or role escalation events

Detection Strategies

Inspect HTTP request bodies sent to ConveyThis plugin endpoints for serialized PHP object patterns
Hunt for unserialize() invocations on request-derived variables within the plugin source
Correlate authenticated administrator activity with anomalous PHP child process creation
Review WordPress audit logs for privileged actions performed shortly before suspicious file changes

Monitoring Recommendations

Enable file integrity monitoring across the WordPress installation, especially within plugin directories
Forward web server, PHP error, and WordPress audit logs to a central SIEM for correlation
Alert on PHP processes spawning shell, curl, wget, or other command-line utilities
Track failed and successful administrator logins to detect credential abuse preceding exploitation

How to Mitigate CVE-2025-57919

Immediate Actions Required

Update the ConveyThis conveythis-translate plugin to a version released after 269.1 once the vendor publishes a fix
Restrict administrator and high-privilege account access using strong, unique credentials and multi-factor authentication
Audit recent privileged activity and plugin endpoint requests for signs of exploitation
Take a verified backup of the site before applying changes to support rollback and forensics

Patch Information

The vulnerability affects ConveyThis conveythis-translate from unspecified versions through 269.1. Site operators should monitor the Patchstack advisory and the official plugin listing for a patched release and apply it as soon as it is available.

Workarounds

Deactivate and remove the ConveyThis plugin until a patched version is installed
Deploy a web application firewall rule that blocks serialized PHP payloads (O: and a: prefixed strings) on plugin endpoints
Limit access to /wp-admin and plugin endpoints by IP allowlisting where feasible
Reduce the number of accounts with administrative privileges to shrink the exploitable attack surface

bash

# Example WAF rule (ModSecurity) blocking serialized PHP objects on plugin endpoints
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
  "chain,deny,status:403,id:1057919,msg:'Possible PHP Object Injection (CVE-2025-57919)'"
  SecRule ARGS|REQUEST_BODY "@rx (?:^|[=&])O:\d+:\"[A-Za-z_\\\\]+\":\d+:" \
    "t:none,t:urlDecode"