CVE-2026-84753 in Mail Mint Plugin
Summary
by MITRE • 09/03/2026
Unauthenticated PHP Object Injection in Mail Mint <= 1.31.0 versions.
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Analysis
by VulDB Data Team • 09/03/2026
The vulnerability identified as an unauthenticated PHP object injection flaw within Mail Mint versions prior to or equal to 1.31.0 represents a critical security deficiency that allows attackers to execute arbitrary code on the target server without requiring valid credentials. This type of vulnerability stems from the improper handling of user-supplied input during the deserialization process, where data is converted back into PHP objects in an unsafe manner. In many modern web applications, including those built with frameworks like Laravel which Mail Mint utilizes, serialization is often employed to store session data or cache information. When these serialized strings are derived directly from HTTP requests without sufficient validation or sanitization, they become a vector for exploitation. The attacker crafts a malicious payload containing a specially constructed PHP object that triggers unintended side effects when the application attempts to unserialize it, effectively bypassing any authentication mechanisms because the entry point does not require prior login access.
From a technical perspective, this flaw is classified under CWE-502, which denotes Deserialization of Untrusted Data. The core issue lies in the fact that PHP allows for magic methods such as __wakeup(), __destruct(), and __toString() to be automatically invoked during deserialization if they exist within the class definition being instantiated. By manipulating the serialized string, an attacker can instantiate classes available in the application's environment or its dependencies, leading to Remote Code Execution (RCE). This is particularly dangerous because it does not rely on traditional input validation bypasses but rather exploits the internal logic of how PHP handles object reconstruction. The lack of authentication means that any user interacting with the vulnerable endpoint, whether through a web browser, command-line tool like curl, or automated scanning scripts, can trigger this code execution path.
The operational impact of this vulnerability is severe, potentially resulting in complete compromise of the underlying server infrastructure. Once an attacker achieves remote code execution via PHP object injection, they are not limited to just viewing data; they can read sensitive configuration files containing database credentials and API keys, modify application logic to create backdoors, or pivot further into the internal network. In the context of a mail management plugin like Mail Mint, this could also lead to unauthorized access to email accounts stored within the system, resulting in significant privacy breaches and potential misuse for spamming or phishing campaigns using trusted domains associated with the victim organization. The ability to execute commands as the web server user often grants privileges sufficient to install rootkits, exfiltrate customer data, or disrupt service availability through denial-of-service attacks initiated from within the application layer.
Industry frameworks categorize this behavior under ATT&CK technique T1059, specifically Command and Scripting Interpreter sub-techniques, as well as T1203 for Exploitation for Client Execution if the payload targets client-side components, though in server-side PHP contexts it primarily aligns with direct system command execution. Mitigation strategies must prioritize immediate patching to version 1.31.1 or later where this deserialization issue has been addressed by developers through strict input validation and whitelisting of allowed classes during unserialization processes. Organizations should also implement Web Application Firewalls configured to detect anomalous serialized data patterns in HTTP requests, although reliance on WAFs is not a substitute for fixing the root cause. Additionally, enabling PHP's disable_functions directive to restrict dangerous functions like exec, system, and passthru can reduce the blast radius if an injection attempt succeeds, serving as a defensive-in-depth measure while remediation efforts are underway.