CVE-2026-27306: Adobe ColdFusion RCE Vulnerability

CVE-2026-27306 Overview

CVE-2026-27306 is an Improper Input Validation vulnerability affecting Adobe ColdFusion versions 2023.18, 2025.6 and earlier. This vulnerability could allow an attacker to achieve arbitrary code execution in the context of the current user. Successful exploitation requires the attacker to have elevated privileges and depends on user interaction, specifically requiring a victim to open a malicious file.

Critical Impact

This vulnerability enables arbitrary code execution with user-level permissions, potentially allowing attackers to compromise ColdFusion server environments, access sensitive data, or establish persistence on affected systems.

Affected Products

• Adobe ColdFusion 2023 (all updates through Update 18)
• Adobe ColdFusion 2025 (all updates through Update 6)
• Adobe ColdFusion 2023 base installation and all intermediate updates (Update 1 through Update 17)

Discovery Timeline

• 2026-04-14 - CVE-2026-27306 published to NVD
• 2026-04-16 - Last updated in NVD database

Technical Details for CVE-2026-27306

Vulnerability Analysis

This vulnerability stems from improper input validation (CWE-20) within Adobe ColdFusion's file processing mechanisms. When a specially crafted malicious file is processed by a user with elevated privileges, the application fails to properly sanitize or validate input data, creating an opportunity for arbitrary code execution.

The attack requires adjacent network access rather than remote exploitation over the internet, meaning an attacker must be positioned within the same network segment or logical network boundary as the target ColdFusion server. The requirement for elevated privileges (administrator or high-privilege account) and user interaction provides some mitigation, as the attack cannot be fully automated against arbitrary targets.

The code execution occurs within the security context of the current user who opens the malicious file. Given that administrators typically interact with ColdFusion configuration and management files, successful exploitation could result in full server compromise with administrative-level access to the ColdFusion environment.

Root Cause

The vulnerability originates from inadequate input validation routines within ColdFusion's file handling components. When processing certain file types or content, the application fails to properly sanitize user-supplied data before using it in security-sensitive operations. This lack of validation allows maliciously crafted input to escape the intended processing context and execute arbitrary code.

Attack Vector

The attack vector for CVE-2026-27306 requires an adjacent network position, elevated user privileges, and user interaction. An attacker would need to:

1. Gain access to the same network segment as the target ColdFusion server
2. Craft a malicious file designed to exploit the input validation flaw
3. Deliver the malicious file to a privileged user (through social engineering, shared network resources, or other means)
4. Wait for the victim to open the malicious file within the ColdFusion environment

The combination of these requirements makes this a targeted attack scenario rather than a widespread opportunistic exploit. However, in environments where these conditions are met, the impact is severe due to the code execution capability.

Detection Methods for CVE-2026-27306

Indicators of Compromise

• Unexpected file access or processing events in ColdFusion logs involving privileged user accounts
• Anomalous code execution or process spawning from ColdFusion server processes
• Unusual network connections originating from ColdFusion services after file operations
• Suspicious files with non-standard content appearing in ColdFusion directories

Detection Strategies

• Implement file integrity monitoring on ColdFusion installation directories and configuration files
• Monitor ColdFusion application logs for errors related to file processing or input validation failures
• Configure endpoint detection to alert on unusual child processes spawned by ColdFusion server processes
• Deploy network monitoring to detect lateral movement from ColdFusion servers following potential compromise

Monitoring Recommendations

• Enable verbose logging for ColdFusion file operations and administrative actions
• Implement user behavior analytics to detect anomalous activity patterns from privileged accounts
• Monitor for unusual authentication events to ColdFusion administrative interfaces from adjacent network segments
• Configure alerts for any code execution attempts or shell spawning from the ColdFusion service context

How to Mitigate CVE-2026-27306

Immediate Actions Required

• Apply the latest security patches from Adobe for ColdFusion 2023 and 2025 as documented in Adobe Security Bulletin APSB26-38
• Restrict ColdFusion administrative access to trusted users and enforce the principle of least privilege
• Implement network segmentation to limit adjacent network access to ColdFusion servers
• Educate privileged users about the risks of opening untrusted files within the ColdFusion environment

Patch Information

Adobe has released security updates to address this vulnerability. Refer to the Adobe ColdFusion Security Advisory (APSB26-38) for detailed patch information and download links. Organizations should prioritize updating to ColdFusion 2023 Update 19 or later, and ColdFusion 2025 Update 7 or later.

Workarounds

• Restrict administrative access to ColdFusion to a minimal set of trusted users until patches can be applied
• Implement strict file upload and processing policies to prevent untrusted files from reaching privileged users
• Deploy application-level firewalls to inspect and filter potentially malicious file content
• Consider temporarily disabling file processing features that may be affected if operationally feasible

# Restrict ColdFusion administrative access via IP filtering
# Add to your web server configuration (example for Apache)
<Location /CFIDE/administrator>
    Require ip 10.0.0.0/8
    Require ip 192.168.1.0/24
</Location>