CVE-2018-15961

What is Adobe ColdFusion?

Adobe ColdFusion is a commercial rapid web application development platform used by enterprises, government agencies, and universities to build dynamic websites and business applications using the CFML scripting language. ColdFusion has a long track record of serious remote code execution vulnerabilities, and because it typically runs with significant privileges on the underlying server (often Windows/IIS or Java-based deployments), a compromise of ColdFusion often means full server compromise.

Overview

CVE-2018-15961 is an unrestricted file upload vulnerability in Adobe ColdFusion that allows an attacker to upload a malicious file (such as a web shell written in CFML) to the server without adequate restriction on file type or destination. Once uploaded to a web-accessible directory, the file can be invoked directly by the attacker, resulting in arbitrary code execution in the context of the ColdFusion application server.

Technical Details

The root cause (CWE-434, Unrestricted Upload of File with Dangerous Type) is that a ColdFusion component fails to properly validate uploaded file extensions/content before storing them in a location where the web server will execute them as server-side scripts. This is a classic and highly reliable RCE pattern: no memory corruption or complex chaining is needed — the attacker simply uploads executable code disguised as a permitted file type, then requests it directly to have the server execute it, with no authentication required (CVSS 9.8).

Discovery

The vulnerability was addressed by Adobe through its regular ColdFusion security bulletin process, alongside fixes for other ColdFusion vulnerabilities disclosed around the same time.

Exploitation Context

CISA's KEV entry confirms this vulnerability has been exploited in the wild. ColdFusion unrestricted file upload and deserialization bugs have historically been popular targets for both opportunistic web shell campaigns and more sophisticated intrusion sets, given ColdFusion's continued use in legacy enterprise and government web applications that are often not promptly patched.

Remediation

1. Apply the Adobe ColdFusion security update that addresses this CVE for your ColdFusion version immediately.
2. Restrict or disable unnecessary ColdFusion components and administrative endpoints not required for the application's function.
3. Configure the web server to prevent execution of scripts from upload directories (e.g., disallow CFM/CFC execution in folders intended only for user-uploaded content).
4. Scan the web root for unexpected .cfm/.cfc files that may indicate a web shell was already planted.
5. Review ColdFusion and web server access logs for unusual file upload activity or requests to unfamiliar uploaded files.