CVE-2026-25737 in budibase
Summary
by MITRE • 03/09/2026
Budibase is a low code platform for creating internal tools, workflows, and admin panels. In 3.24.0 and earlier, an arbitrary file upload vulnerability exists even though file extension restrictions are configured. The restriction is enforced only at the UI level. An attacker can bypass these restrictions and upload malicious files.
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Analysis
by VulDB Data Team • 03/14/2026
The vulnerability identified as CVE-2026-25737 represents a critical arbitrary file upload flaw in Budibase versions 3.24.0 and earlier, where the platform's security controls fail to properly validate file extensions at the server level despite client-side restrictions being implemented. This type of vulnerability falls under the category of insecure file handling and directly relates to CWE-434 which addresses the improper restriction of file uploads. The security mechanism in place relies entirely on user interface level validation, creating a fundamental weakness that allows attackers to bypass client-side controls through direct API calls or modified requests.
The technical implementation of this vulnerability stems from the platform's architecture where file extension validation occurs exclusively within the frontend interface components rather than being enforced through robust server-side validation mechanisms. This architectural flaw enables attackers to upload malicious files such as web shells, scripts, or executable content without proper authorization. The bypass mechanism typically involves crafting HTTP requests that circumvent the UI validation by directly interacting with backend APIs, effectively rendering the client-side restrictions meaningless. This weakness creates a path for attackers to execute arbitrary code on the server, potentially leading to complete system compromise.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with the capability to establish persistent access to the affected system. An attacker who successfully exploits this vulnerability can upload malicious files that may include web shells, reverse shells, or other malicious executables, enabling them to gain unauthorized access to the system and potentially escalate privileges. The vulnerability also creates opportunities for lateral movement within the network and data exfiltration, as attackers can establish backdoors and maintain persistence. The low code nature of Budibase means that the platform may be used to create business-critical applications, making the compromise of such systems particularly damaging to organizations. This vulnerability directly maps to several ATT&CK techniques including T1190 for exploiting vulnerabilities, T1059 for command and scripting interpreter, and T1078 for valid accounts.
Mitigation strategies for this vulnerability require immediate implementation of robust server-side validation controls that enforce file extension restrictions at the application layer rather than relying solely on frontend validation. Organizations should implement comprehensive file type validation that checks file headers, MIME types, and extensions against a strict whitelist of allowed formats. The platform should be updated to version 3.24.1 or later where the vulnerability has been addressed through proper server-side enforcement of file upload restrictions. Additionally, implementing network segmentation, monitoring for unusual file upload activities, and conducting regular security assessments can help detect and prevent exploitation attempts. Access controls should be reviewed to ensure that only authorized personnel can upload files, and the principle of least privilege should be enforced for all user accounts. Security teams should also consider implementing web application firewalls and intrusion detection systems to monitor for suspicious upload patterns and potential exploitation attempts.