Overview
A critical vulnerability, identified as CVE-2025-12974, has been discovered in the Gravity Forms plugin for WordPress. This vulnerability allows unauthenticated attackers to upload arbitrary files, potentially leading to remote code execution (RCE) on the affected server. The vulnerability resides in the legacy chunked upload mechanism and affects all Gravity Forms versions up to, and including, 2.9.21.1. Failure to address this vulnerability can result in severe consequences, including website defacement, data theft, and complete server compromise.
Technical Details
The vulnerability stems from inadequate file type validation in the legacy chunked upload mechanism. Specifically, the extension blacklist implemented in Gravity Forms does not include the .phar file extension. An attacker can exploit this by uploading a malicious .phar file via the chunked upload functionality.
To achieve RCE, the attacker needs to discover or enumerate the upload path of the uploaded file. Furthermore, the web server configuration must be set up to process .phar files as PHP code, either through file handler mapping or similar configurations. Without this server-side configuration, the attacker will not be able to execute the malicious code. This is a common configuration in many default server setups, increasing the risk.
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) assigns this vulnerability a score of 8.1, classifying it as HIGH severity. This score reflects the potential for significant impact due to remote code execution capabilities without authentication.
Possible Impact
Successful exploitation of CVE-2025-12974 can have devastating consequences:
- Remote Code Execution (RCE): Attackers can execute arbitrary code on the server, gaining complete control.
- Website Defacement: Attackers can modify website content, damaging the reputation of the affected organization.
- Data Theft: Sensitive data stored on the server, including user credentials and customer information, can be stolen.
- Backdoor Installation: Attackers can install backdoors to maintain persistent access to the compromised server.
- Complete Server Compromise: Attackers can gain full control over the server, potentially using it to launch further attacks.
Mitigation and Patch Steps
The most effective way to mitigate this vulnerability is to update Gravity Forms to the latest version. Versions after 2.9.21.1 address this vulnerability. You can update the plugin through your WordPress dashboard.
If immediate updating is not possible, consider the following temporary mitigation steps:
- Restrict .phar file processing on the web server: Modify your server configuration to prevent
.pharfiles from being executed as PHP. This typically involves modifying the Apache or Nginx configuration. This is a highly recommended temporary fix if updating isn’t immediately feasible. - Monitor file uploads: Implement monitoring mechanisms to detect suspicious file uploads.
- Web Application Firewall (WAF): Utilize a WAF with rules to block the upload of
.pharfiles.
