CVE-2026-27305 Overview
CVE-2026-27305 is a path traversal vulnerability affecting Adobe ColdFusion versions 2023.18, 2025.6, and earlier. The flaw stems from improper limitation of a pathname to a restricted directory [CWE-22], allowing unauthenticated attackers to read arbitrary files on the underlying file system. Exploitation requires no user interaction and can be performed remotely over the network. An attacker can leverage this issue to access sensitive files and directories outside the intended scope, including configuration files, credentials, and application source code.
Critical Impact
Unauthenticated remote attackers can read arbitrary files on vulnerable ColdFusion servers, exposing credentials, configuration data, and proprietary application logic without any user interaction.
Affected Products
- Adobe ColdFusion 2023 (including updates 1 through 18)
- Adobe ColdFusion 2025 (including updates 1 through 6)
- Adobe ColdFusion 2023.18, 2025.6 and earlier
Discovery Timeline
- 2026-04-14 - CVE-2026-27305 published to NVD
- 2026-04-16 - Last updated in NVD database
Technical Details for CVE-2026-27305
Vulnerability Analysis
The vulnerability is classified as Improper Limitation of a Pathname to a Restricted Directory [CWE-22]. Adobe ColdFusion fails to properly normalize and validate user-supplied path components before resolving them against the server file system. An attacker can craft a request containing directory traversal sequences such as ../ to escape the application's intended directory boundaries. The scope-changing nature of this flaw means a successful exploit affects resources beyond the vulnerable component itself, increasing the blast radius across the host. Because authentication is not required, any network-reachable ColdFusion endpoint is exposed.
Root Cause
The root cause is insufficient input sanitization on file path parameters processed by ColdFusion. When the application constructs file system paths from request data, it does not canonicalize the input or enforce a strict allow-list of directories. Encoded traversal sequences and absolute path overrides are not stripped or rejected, allowing the resolved path to point outside the intended web root or restricted directory.
Attack Vector
The attack vector is network-based and requires no privileges or user interaction. An attacker sends a specially crafted HTTP request to a ColdFusion endpoint that handles file references. By embedding path traversal sequences in the parameter value, the attacker forces the server to read files outside the permitted directory. Typical targets include neo-security.xml, password.properties, seed.properties, and OS-level files such as /etc/passwd or Windows registry hive backups. Refer to the Adobe ColdFusion Security Advisory APSB26-38 for vendor-supplied technical details.
Detection Methods for CVE-2026-27305
Indicators of Compromise
- HTTP requests containing path traversal sequences such as ../, ..%2f, or ..%5c directed at ColdFusion endpoints
- Unexpected file read access to neo-*.xml, password.properties, or seed.properties outside of normal administrative workflows
- Outbound traffic patterns following anomalous reads of ColdFusion configuration files
- ColdFusion log entries showing file access errors for paths outside the application directory
Detection Strategies
- Inspect web server and ColdFusion access logs for URL-encoded or double-encoded traversal patterns targeting .cfm and .cfc handlers
- Deploy web application firewall rules to flag requests containing traversal payloads on ColdFusion virtual hosts
- Correlate file read events on sensitive ColdFusion configuration files with the source HTTP request session
- Hunt for sequential file enumeration attempts originating from a single source IP within short time windows
Monitoring Recommendations
- Enable verbose request logging on ColdFusion application servers and forward logs to a centralized analytics platform
- Monitor process-level file access on the ColdFusion service account for reads outside the expected web root
- Alert on access to sensitive paths such as WEB-INF/cfusion/lib/, cfusion/lib/, and operating system credential stores
- Track baseline request rates per endpoint and alert on spikes that may indicate automated exploitation
How to Mitigate CVE-2026-27305
Immediate Actions Required
- Apply the Adobe security update referenced in Adobe Security Bulletin APSB26-38 to all ColdFusion 2023 and 2025 installations
- Inventory all internet-facing ColdFusion instances and prioritize patching of externally exposed servers
- Review web server and ColdFusion logs for traversal patterns dating back at least 90 days
- Rotate credentials and secrets stored in ColdFusion configuration files if compromise is suspected
Patch Information
Adobe has released fixed versions addressing CVE-2026-27305. Administrators should upgrade ColdFusion 2023 to a release later than update 18 and ColdFusion 2025 to a release later than update 6, as specified in the Adobe ColdFusion Security Advisory. Verify the installed update level using the ColdFusion Administrator console after applying patches.
Workarounds
- Restrict network exposure of ColdFusion administration endpoints to trusted management networks only
- Deploy a web application firewall with rules blocking common path traversal payloads against ColdFusion virtual hosts
- Enforce least-privilege file system permissions on the ColdFusion service account to limit readable directories
- Disable or remove unused ColdFusion components and handlers that accept file path parameters
# Example WAF rule pattern to block traversal attempts on ColdFusion endpoints
# ModSecurity-style rule
SecRule REQUEST_URI "@rx (\.\./|\.\.%2f|\.\.%5c|%2e%2e/)" \
"id:1027305,phase:1,deny,status:403,\
msg:'CVE-2026-27305 ColdFusion path traversal attempt blocked'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
