CVE-2026-27305: Adobe ColdFusion Path Traversal Flaw

CVE-2026-27305 Overview

CVE-2026-27305 is a Path Traversal vulnerability affecting Adobe ColdFusion versions 2023.18, 2025.6 and earlier. This vulnerability allows an attacker to exploit improper limitation of a pathname to a restricted directory, enabling arbitrary file system read operations. Successful exploitation permits access to sensitive files and directories outside the intended access scope without requiring any user interaction.

Critical Impact

Unauthenticated attackers can remotely access sensitive files on affected ColdFusion servers, potentially exposing configuration files, credentials, application source code, and other confidential data stored on the file system.

Affected Products

• Adobe ColdFusion 2023 (all updates through Update 18)
• Adobe ColdFusion 2025 (all updates through Update 6)
• All prior versions of the affected product lines

Discovery Timeline

• April 14, 2026 - CVE-2026-27305 published to NVD
• April 16, 2026 - Last updated in NVD database

Technical Details for CVE-2026-27305

Vulnerability Analysis

This Path Traversal vulnerability (CWE-22) stems from insufficient validation of user-supplied input in file path handling within Adobe ColdFusion. The vulnerability enables attackers to craft malicious requests containing directory traversal sequences that bypass intended directory restrictions, allowing read access to arbitrary locations on the server's file system.

The attack requires no authentication or user interaction, making it particularly dangerous for internet-facing ColdFusion deployments. An attacker can leverage this flaw to access sensitive configuration files, database connection strings, API keys, or any other readable files on the affected server. The scope is changed, meaning the vulnerability can affect resources beyond the vulnerable component's security scope.

Root Cause

The root cause of CVE-2026-27305 lies in improper input validation when processing file path parameters. The ColdFusion application fails to adequately sanitize path components, allowing directory traversal sequences such as ../ or encoded variants to escape the intended directory boundaries. This lack of proper canonicalization and path validation enables attackers to navigate outside restricted directories.

Attack Vector

The vulnerability is exploited via network-based requests targeting ColdFusion's file handling functionality. An attacker constructs a request containing path traversal sequences designed to reach files outside the application's document root or configured directory restrictions.

Typical attack patterns involve:

• Submitting requests with sequences like ../../../etc/passwd to traverse to system files
• Using URL-encoded traversal sequences (%2e%2e%2f) to bypass basic input filters
• Targeting configuration files containing database credentials or encryption keys
• Accessing application source code to identify additional vulnerabilities

The attack complexity is low, requires no privileges or authentication, and can be executed without any user interaction, making automated exploitation highly feasible.

Detection Methods for CVE-2026-27305

Indicators of Compromise

• Web server access logs containing path traversal sequences such as ../, ..%2f, %2e%2e/, or ....// in request URLs
• Requests attempting to access sensitive system files like /etc/passwd, web.xml, neo-datasource.xml, or Windows system files
• Unusual file access patterns in ColdFusion application logs showing reads outside normal application directories
• Failed or successful access attempts to ColdFusion configuration directories or parent paths

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block path traversal patterns in HTTP requests
• Implement intrusion detection signatures for ColdFusion-specific exploitation attempts targeting known vulnerable endpoints
• Enable detailed file access auditing on the ColdFusion server to track abnormal file read operations
• Monitor for requests with unusual depth of directory traversal attempts or encoded path components

Monitoring Recommendations

• Configure alerting on web server logs for requests matching path traversal regular expressions
• Enable ColdFusion's built-in request logging and monitor for suspicious file access patterns
• Implement network-level monitoring for traffic to ColdFusion servers containing traversal indicators
• Use SentinelOne's Singularity platform to detect post-exploitation activities and lateral movement following potential compromise

How to Mitigate CVE-2026-27305

Immediate Actions Required

• Apply the latest Adobe ColdFusion security updates addressing CVE-2026-27305 immediately
• Review web server access logs for any indicators of exploitation attempts
• Audit exposed ColdFusion instances and ensure they are behind appropriate security controls
• Consider temporarily restricting external access to ColdFusion servers until patches are applied

Patch Information

Adobe has released security updates to address this vulnerability as documented in security bulletin APSB26-38. Organizations should update to ColdFusion 2023 Update 19 or later, and ColdFusion 2025 Update 7 or later. Review the official Adobe ColdFusion Security Advisory for complete patch details and deployment guidance.

Workarounds

• Implement WAF rules to filter requests containing path traversal sequences before they reach ColdFusion
• Restrict network access to ColdFusion administration interfaces and sensitive endpoints
• Configure web server directory restrictions to limit accessible paths at the server level
• Enable ColdFusion's sandbox security features to constrain file system access permissions

# Example: Apache mod_security rule to block path traversal attempts
SecRule REQUEST_URI|ARGS|ARGS_NAMES "@rx (\.\./|\.\.\\)" \
    "id:1001,phase:2,deny,status:403,log,msg:'Path Traversal Attempt Blocked'"