CVE-2025-2376: Pair Framework Deserialization RCE Flaw

CVE-2025-2376 Overview

CVE-2025-2376 is an insecure deserialization vulnerability in the viames Pair Framework through version 1.9.11. The flaw resides in the getCookieContent function within /src/UserRemember.php, part of the PHP Object Handler component. Attackers can manipulate the cookieName argument to trigger deserialization of attacker-controlled data. The vulnerability is remotely exploitable without authentication, and a proof-of-concept exploit has been publicly disclosed. The issue is tracked under [CWE-20] Improper Input Validation and affects applications built on the affected framework versions.

Critical Impact

Remote attackers can supply crafted cookie data to invoke PHP object deserialization, enabling potential object injection against applications running viames Pair Framework <= 1.9.11.

Affected Products

• viames Pair Framework versions up to and including 1.9.11
• Component: PHP Object Handler (/src/UserRemember.php)
• Function: getCookieContent

Discovery Timeline

• 2025-03-17 - CVE-2025-2376 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-2376

Vulnerability Analysis

The Pair Framework is a PHP application framework that includes a "remember me" feature implemented in UserRemember.php. The getCookieContent function accepts a cookieName argument and processes the corresponding cookie value through PHP deserialization without adequate validation of the input source or content.

Because cookies are client-controlled, an attacker can submit a forged cookie containing a serialized PHP object. When the framework calls unserialize() on the attacker-supplied data, any magic methods such as __wakeup(), __destruct(), or __toString() on reachable classes execute within the application context. This pattern, known as PHP Object Injection, can lead to arbitrary file operations, data tampering, or code execution depending on the gadget chains available in the host application.

The EPSS score is 0.197% at the 41.366 percentile, indicating low observed exploitation activity despite public disclosure of a proof of concept.

Root Cause

The root cause is improper input validation on serialized data sourced from HTTP cookies. The framework trusts cookie content as a legitimate serialized payload and passes it to PHP's native deserialization routine without integrity verification, type filtering, or use of safer alternatives such as JSON encoding.

Attack Vector

Exploitation occurs over the network with no privileges and no user interaction. An attacker crafts a malicious serialized PHP object, sets it as the cookie value matching the name expected by getCookieContent, and issues a request to a route that triggers the remember-me handling. The deserialization process instantiates attacker-defined objects, activating any gadget chain present in the loaded codebase.

For technical exploitation details, refer to the GitHub Gist PoC Script and the VulDB Critical Threat Report.

Detection Methods for CVE-2025-2376

Indicators of Compromise

• Inbound HTTP requests containing cookie values that begin with PHP serialization markers such as O:, a:, or s: followed by length-prefixed object data.
• PHP error logs referencing unserialize() warnings, missing class definitions, or __wakeup/__destruct invocations originating from UserRemember.php.
• Unexpected file writes, outbound connections, or process activity tied to the web server user after requests carrying remember-me cookies.

Detection Strategies

• Inspect web server and application logs for requests targeting routes that invoke the Pair Framework remember-me flow with anomalously long or binary-looking cookie values.
• Deploy web application firewall (WAF) rules that flag serialized PHP object patterns inside cookie headers.
• Perform static analysis of deployed applications to identify all callers of getCookieContent and audit the version of Pair Framework in use.

Monitoring Recommendations

• Forward PHP-FPM and web server logs to a centralized analytics platform and alert on unserialize warnings correlated with cookie-bearing requests.
• Monitor for child processes spawned by the PHP runtime that deviate from expected application behavior.
• Track outbound network connections initiated by web server processes to detect post-exploitation activity.

How to Mitigate CVE-2025-2376

Immediate Actions Required

• Identify all applications using viames Pair Framework <= 1.9.11 and prioritize upgrade to a patched release once available.
• Invalidate existing remember-me cookies by rotating the application secret and forcing user re-authentication.
• Restrict access to authentication endpoints with WAF rules that reject cookies containing PHP serialization signatures.

Patch Information

No official vendor advisory URL is listed in the NVD record at this time. Consult the VulDB Submission Details and the project's repository for the latest fixed version. Upgrade to a release later than 1.9.11 once published by the maintainer.

Workarounds

• Replace unserialize() usage in custom forks of UserRemember.php with json_decode() against a JSON-encoded cookie payload, or use unserialize($data, ['allowed_classes' => false]) to block object instantiation.
• Sign remember-me cookies with an HMAC and reject any cookie whose signature does not validate before deserialization occurs.
• Disable the remember-me feature entirely in affected deployments until a patched framework version is installed.

# Configuration example: reject serialized PHP objects in cookies at the WAF layer
# ModSecurity rule snippet
SecRule REQUEST_COOKIES "@rx ^[Oa]:[0-9]+:" \
    "id:1002376,phase:1,deny,status:400,\
    msg:'Possible PHP object injection via cookie (CVE-2025-2376)',\
    tag:'attack-deserialization'"