CVE-2026-7654
Summary
by MITRE • 06/06/2026
The Admin Columns plugin for WordPress is vulnerable to PHP Object Injection leading to Remote Code Execution in versions up to and including 7.0.18. This is due to the use of `unserialize()` without an `allowed_classes` restriction in the `IdsToCollection::get_ids_from_string()` function, which processes attacker-controlled post meta values without proper validation. This makes it possible for authenticated attackers with Contributor-level access and above to inject a serialized PHP object into a post's custom meta field and trigger arbitrary code execution by exploiting a bundled POP gadget chain, resulting in remote code execution as the web server user.
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Analysis
by VulDB Data Team • 06/06/2026
The Admin Columns plugin for WordPress presents a critical security vulnerability classified as PHP Object Injection that can lead to Remote Code Execution affecting versions up to and including 7.0.18. This vulnerability stems from improper handling of serialized data within the plugin's codebase, specifically in the IdsToCollection::get_ids_from_string() function. The flaw occurs when the plugin processes post meta values that contain serialized PHP objects without implementing adequate restrictions on allowed classes during the unserialization process. This vulnerability is particularly concerning because it requires only Contributor-level access or higher to exploit, making it accessible to users who should not have the ability to execute arbitrary code on the target system.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-502, which describes the weakness of deserializing untrusted data without proper validation. Attackers can manipulate post meta fields to inject malicious serialized PHP objects that contain a chain of object propagation gadgets. These gadgets, when triggered through the vulnerable unserialize() call, can execute arbitrary code on the web server with the privileges of the web user account. The attack vector is particularly dangerous because it leverages legitimate plugin functionality to deliver malicious payloads, making detection more challenging and allowing attackers to remain undetected while establishing persistent access to the compromised system.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to fully compromise the WordPress installation and potentially gain access to the underlying server infrastructure. Since the vulnerability affects the web server user context, attackers can leverage this access to modify or delete content, steal sensitive data, install backdoors, or even escalate privileges further within the compromised environment. The fact that this vulnerability requires minimal privilege levels makes it particularly attractive to threat actors who may be able to gain access through compromised user accounts or social engineering attacks that result in Contributor-level permissions.
Security mitigations for this vulnerability should prioritize immediate plugin updates to versions that have addressed the issue through proper input validation and the implementation of allowed_classes parameter in unserialize() calls. Organizations should also implement network monitoring to detect suspicious serialization patterns in post meta data and consider restricting user permissions to minimize the attack surface. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing: Spearphishing Attachment) and T1059.007 (Command and Scripting Interpreter: Python) as attackers may use this vulnerability to establish persistent access and execute commands on compromised systems. Additionally, implementing proper input sanitization and output encoding practices in all plugin development can prevent similar vulnerabilities from occurring in the future, aligning with the security principles outlined in the OWASP Top Ten and NIST Cybersecurity Framework.