CVE-2023-26359: Adobe ColdFusion RCE Vulnerability

CVE-2023-26359 Overview

Adobe ColdFusion versions 2018 Update 15 (and earlier) and 2021 Update 5 (and earlier) are affected by a Deserialization of Untrusted Data vulnerability (CWE-502) that could result in arbitrary code execution in the context of the current user. This vulnerability is particularly dangerous because exploitation does not require user interaction, allowing attackers to remotely compromise affected systems without any victim involvement.

Critical Impact

This vulnerability is actively exploited in the wild and has been added to the CISA Known Exploited Vulnerabilities (KEV) catalog. Organizations running vulnerable ColdFusion versions face significant risk of complete system compromise through remote code execution.

Affected Products

• Adobe ColdFusion 2018 Update 15 and all earlier updates
• Adobe ColdFusion 2021 Update 5 and all earlier updates
• Adobe ColdFusion 2018 base release through Update 15

Discovery Timeline

• March 23, 2023 - CVE-2023-26359 published to NVD
• October 23, 2025 - Last updated in NVD database

Technical Details for CVE-2023-26359

Vulnerability Analysis

This vulnerability stems from insecure deserialization practices within Adobe ColdFusion's handling of untrusted data. Insecure deserialization occurs when an application deserializes data from untrusted sources without proper validation, allowing attackers to manipulate serialized objects to execute arbitrary code. In the context of ColdFusion, this vulnerability enables unauthenticated remote attackers to achieve code execution in the context of the current user, which typically runs with elevated privileges on the web server.

The network-accessible nature of this vulnerability combined with the lack of required authentication or user interaction makes it an attractive target for threat actors. Organizations exposing ColdFusion servers to the internet are at heightened risk.

Root Cause

The root cause of CVE-2023-26359 is improper handling of serialized Java objects within Adobe ColdFusion. The application fails to adequately validate or sanitize serialized data before deserialization, allowing malicious payloads crafted by attackers to be processed. When these malicious serialized objects are deserialized, they can trigger code execution through gadget chains present in the application's classpath.

Attack Vector

This vulnerability is exploitable over the network without requiring authentication or user interaction. Attackers can craft malicious serialized Java objects and send them to vulnerable ColdFusion endpoints. When the server deserializes these objects, the embedded payload executes arbitrary commands with the privileges of the ColdFusion service account.

The attack typically involves identifying exposed ColdFusion instances, crafting serialized payloads using known Java deserialization gadget chains, and transmitting these payloads to vulnerable endpoints. Successful exploitation grants attackers full control over the affected server.

Detection Methods for CVE-2023-26359

Indicators of Compromise

• Unusual outbound network connections from ColdFusion server processes
• Unexpected Java process spawning or command execution originating from cfusion.exe or ColdFusion Java processes
• Web server logs showing suspicious POST requests with binary or Base64-encoded payloads to ColdFusion endpoints
• Evidence of webshells or backdoors in ColdFusion directories

Detection Strategies

• Monitor ColdFusion access logs for abnormal request patterns, particularly large POST requests to application endpoints
• Implement network-based detection rules to identify serialized Java object signatures in HTTP traffic
• Deploy endpoint detection and response (EDR) solutions to detect anomalous process behavior from ColdFusion services
• Use web application firewalls (WAF) configured to inspect and block suspicious serialized object patterns

Monitoring Recommendations

• Enable verbose logging on ColdFusion servers and centralize log collection for analysis
• Monitor for process creation events from ColdFusion parent processes, especially command interpreters like cmd.exe or /bin/sh
• Implement file integrity monitoring on ColdFusion installation directories and web roots
• Track network connections initiated by ColdFusion processes for unusual destinations or protocols

How to Mitigate CVE-2023-26359

Immediate Actions Required

• Update Adobe ColdFusion 2018 to Update 16 or later immediately
• Update Adobe ColdFusion 2021 to Update 6 or later immediately
• If immediate patching is not possible, restrict network access to ColdFusion administration interfaces and application endpoints
• Review server logs for evidence of exploitation and conduct incident response if compromise is suspected

Patch Information

Adobe has released security patches addressing this vulnerability in security bulletin APSB23-25. Organizations should apply the following updates:

• ColdFusion 2018: Update to Update 16 or later
• ColdFusion 2021: Update to Update 6 or later

Given that this vulnerability is listed in the CISA Known Exploited Vulnerabilities Catalog, federal agencies and organizations following CISA guidance are required to remediate this vulnerability according to specified timelines.

Workarounds

• Implement network segmentation to isolate ColdFusion servers from direct internet access
• Deploy a reverse proxy or web application firewall in front of ColdFusion to filter malicious requests
• Disable unnecessary ColdFusion features and services to reduce the attack surface
• Apply principle of least privilege to the ColdFusion service account to limit impact of successful exploitation

# Example: Restrict access to ColdFusion Administrator (Apache httpd.conf)
<Location /CFIDE/administrator>
    Require ip 10.0.0.0/8
    Require ip 192.168.0.0/16
</Location>

# Example: Block external access to sensitive endpoints
<Location /CFIDE>
    Require ip 127.0.0.1
</Location>