Forminator Forms Plugin Unsafe Deserialization Remote Code Execution

The Forminator Forms WordPress plugin before 1.57.2.1 does not restrict which classes may be instantiated when it deserialises a value taken from an XML-RPC request, allowing users who hold its forms-management permission to write a file of their choosing and execute arbitrary code. That permission belongs to an administrator by default, and to any role the site has granted it through the Forminator Forms WordPress plugin before 1.57.2.1's own settings, so the issue is reachable well below administrator on sites that use that feature.

Casky was already ahead

This CVE exploits attack patterns that Casky's 323matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

Forminator Forms, a popular WordPress plugin, contains a critical unsafe deserialization vulnerability (CWE-94) in its XML-RPC request handling that allows attackers to instantiate arbitrary classes and achieve remote code execution. The vulnerability affects versions before 1.57.2.1 and is exploitable by users with the forms-management permission—a capability typically granted to administrators but potentially delegated to lower-privileged roles through the plugin's settings. This creates a significant risk for WordPress sites using Forminator, as threat actors can abuse the permission model to write files to the server and execute malicious code, potentially leading to full site compromise.

Casky's 323 matched security skills leverage Claude AI's extended reasoning to map this vulnerability across MITRE ATT&CK techniques TA0001 (Initial Access) and TA0043 (Reconnaissance). Practitioners using Casky would identify detection patterns including: XML-RPC requests containing serialized PHP objects with unexpected class instantiations, file write operations originating from web server processes handling form submissions, and suspicious class instantiation chains typical of object injection attacks. The platform's skills would highlight permission escalation risks by correlating forms-management role assignments with low-privileged user accounts, and flag indicators of code execution such as unexpected process spawning or web shell creation following XML-RPC activity. This multi-layered detection approach helps security teams pinpoint both the attack vector and post-exploitation activities before they escalate to full compromise.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

323 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-87067.

Abuse of Public-Facing API: Mobile API Abuse

mobile security · low

Run

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

MITRE ATT&CK Techniques

TA0001 TA0043

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