CVE-2025-12974 in Gravity Forms Plugin
Summary
by MITRE • 11/18/2025
The Gravity Forms plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the legacy chunked upload mechanism in all versions up to, and including, 2.9.21.1. This is due to the extension blacklist not including .phar files, which can be uploaded through the chunked upload mechanism. This makes it possible for unauthenticated attackers to upload executable .phar files and achieve remote code execution on the server, granted they can discover or enumerate the upload path. In order for an attacker to achieve RCE, the web server needs to be set up to process .phar file as PHP via file handler mapping or similar.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 11/19/2025
The vulnerability identified as CVE-2025-12974 affects the Gravity Forms plugin for WordPress, representing a critical security flaw that undermines the integrity of web applications relying on this popular form management solution. This weakness exists within the legacy chunked upload mechanism that has been deprecated but continues to function in versions up to and including 2.9.21.1, creating an exploitable attack surface that has persisted despite the availability of more secure alternatives. The vulnerability stems from inadequate input validation within the file upload process, specifically failing to properly validate file extensions during the chunked upload procedure that allows attackers to bypass standard security measures.
The technical implementation of this flaw involves the absence of .phar file extensions in the extension blacklist mechanism that should prevent potentially dangerous file types from being uploaded to the server. The chunked upload functionality, while designed to handle large file transfers by breaking them into smaller segments, introduces a critical oversight in its validation logic. When attackers upload .phar files through this legacy mechanism, they can successfully bypass the normal file type restrictions because .phar extensions are not included in the security filters. This oversight creates a direct pathway for attackers to execute malicious code on the target server, as .phar files can be processed by the php engine when the web server is configured to treat them as executable PHP code.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads, creating a severe remote code execution risk that can compromise entire web servers. The requirement for attackers to discover or enumerate the upload path adds a layer of complexity but does not eliminate the threat, as directory traversal attacks, path disclosure vulnerabilities, or information leakage in the application can provide the necessary reconnaissance. The attack chain necessitates that the web server be configured to process .phar files as PHP, which can occur through various server configurations including IIS handler mappings or Apache mod_php configurations that treat .phar files as executable. This configuration, while not common, represents a dangerous combination where the vulnerability can be exploited with minimal prerequisites, making it particularly concerning for organizations running WordPress installations with Gravity Forms.
Security practitioners should recognize this vulnerability as a classic example of insecure file upload handling that aligns with CWE-434, which specifically addresses the improper restriction of uploads of executable files. The attack pattern corresponds to techniques described in the ATT&CK framework under T1190 for exploit public-facing application and T1059 for command and scripting interpreter, demonstrating how this vulnerability can enable attackers to establish persistent access and execute arbitrary commands. Organizations should immediately implement mitigations including updating to the latest version of Gravity Forms where this vulnerability has been addressed, implementing additional file validation mechanisms, and configuring web servers to prevent .phar files from being executed as PHP code. Network-level protections such as web application firewalls and upload restrictions should be deployed to prevent exploitation attempts, while regular security audits should verify that no .phar files have been successfully uploaded to the system. The vulnerability also underscores the importance of proper input validation and the dangers of maintaining legacy code paths that may contain unpatched security flaws, highlighting the need for comprehensive security assessments of all plugin and theme components within WordPress installations.