CVE-2026-105899 in ColdFusion
Summary
by MITRE • 10/13/2026
ColdFusion is affected by an Unrestricted Upload of File with Dangerous Type vulnerability that could result in arbitrary code execution in the context of the current user. An attacker could exploit this vulnerability to execute arbitrary code. Exploitation of this issue does not require user interaction. Scope is changed.
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Analysis
by VulDB Data Team • 10/13/2026
The Adobe ColdFusion platform contains a critical security flaw classified as an Unrestricted Upload of File with Dangerous Type, which fundamentally compromises the integrity and availability of server-side applications. This vulnerability arises from insufficient validation mechanisms within the file upload functionality, allowing attackers to bypass expected restrictions on file types. Instead of limiting uploads to safe formats such as images or documents, the application accepts executable scripts or other dangerous file types without adequate sanitization or verification against a whitelist of allowed extensions and MIME types. This lack of rigorous input validation creates a direct pathway for malicious actors to inject harmful content into the server environment, leveraging the trust that ColdFusion places in user-supplied data during upload operations.
From an operational perspective, this flaw enables arbitrary code execution within the context of the current user running the ColdFusion service. This is particularly severe because it represents a change in scope from typical client-side or isolated process vulnerabilities to full server compromise. An attacker does not need any prior authentication or interaction with legitimate users to exploit this issue; they can directly target exposed upload endpoints over the network. Once an executable file, such as a JSP, PHP, or CFM script containing malicious payload code, is successfully uploaded and subsequently accessed by the application, it executes with the privileges of the ColdFusion process. This often grants the attacker administrative-level access to the underlying operating system, allowing them to install backdoors, exfiltrate sensitive data, pivot to other internal systems, or disrupt services entirely.
The technical implications align closely with CWE-434, which describes the unrestricted upload of files with dangerous types, and are further contextualized by MITRE ATT&CK techniques such as T1505.003 (Web Shell: Web Shell) for establishing persistent access and T1059 Command and Scripting Interpreter for executing arbitrary commands on the host system. The absence of required user interaction lowers the barrier to entry significantly, making this vulnerability attractive to automated scanning tools and opportunistic attackers who routinely probe web applications for upload endpoints lacking proper security controls.
Mitigation strategies must focus on implementing strict file validation at both the client and server levels. Developers should enforce a whitelist approach that restricts uploads to only specific, non-executable extensions such as .jpg or .png, while rejecting any executable formats like .jsp, .cfm, or .exe. Additionally, uploaded files should be stored in directories outside of the web root where they cannot be directly executed by the web server. Renaming uploaded files with random strings and storing them in isolated storage buckets can further mitigate risk. For immediate remediation, administrators are advised to apply the latest security patches provided by Adobe for their specific ColdFusion version, as these updates typically include enhanced validation logic and hardened upload handlers designed to prevent such unauthorized file injections.