CVE-2023-26360: Adobe ColdFusion Deserialization of Untrusted Data Vulnerability

CVE-2023-26360 is a vulnerability in Adobe ColdFusion involving deserialization of untrusted data that can allow remote code execution. Successful abuse of this flaw can let an attacker run code on the server hosting ColdFusion, potentially leading to full system compromise, data theft, or further lateral movement.

IT and security teams running ColdFusion should treat this as a high-priority item for inventory and remediation. Confirm all technical details, including exact impact and fixed releases, against the official Adobe vendor advisory rather than relying on secondary summaries.

How it works

The vulnerability is described as a deserialization of untrusted data issue in Adobe ColdFusion, associated with CWE-284. In this class of weakness, the application accepts serialized data from an untrusted source and reconstructs objects from it without adequate validation or access controls.

An attacker who can reach the vulnerable ColdFusion interface can supply crafted input that the deserialization process mishandles. When the application processes that input, it can result in remote code execution under the privileges of the ColdFusion process. Specific exploit mechanics, payloads, or required preconditions are not detailed here and must be confirmed against the vendor advisory; defenders should assume network-accessible ColdFusion endpoints are the primary attack surface for this class of flaw.

Am I affected? How to find it in your systems

Adobe ColdFusion is commonly deployed as an application server for CFML-based web applications, often running on Windows or Linux hosts behind a web server or reverse proxy. It may appear in development, staging, or production environments that host dynamic web content, administrative portals, or internal business applications.

To inventory:

• Search asset management systems, CMDB records, and software inventories for “Adobe ColdFusion” or related CFML runtimes.
• Scan internal networks for hosts listening on typical ColdFusion ports or serving CFML file extensions; review web-server configurations and virtual-host definitions that reference ColdFusion.
• Check installed package lists, Windows Programs and Features, or Linux package managers for ColdFusion installations, then compare the installed version and configuration against the affected product list in the vendor advisory.
• Review configuration files and admin consoles for any features that accept serialized or complex input from remote users.

For signs of exploitation, examine ColdFusion and web-server logs for anomalous requests that contain serialized data structures, unexpected process creation, or outbound connections originating from the ColdFusion service account. Correlate with endpoint detection and response (EDR) telemetry for unusual child processes or file writes under the ColdFusion installation directory. Absence of such indicators does not guarantee safety; proactive version checking remains essential.

How to remediate

The primary remediation is to apply the updates provided by Adobe exactly as described in the vendor advisory. CISA’s required action is to apply updates per vendor instructions; follow Adobe’s guidance for the specific ColdFusion release you run, including any post-install configuration steps or service restarts.

After patching:

• Verify the installed version matches a fixed release listed by the vendor.
• Harden the ColdFusion instance by restricting administrative interfaces to trusted networks, enforcing least-privilege service accounts, and disabling any unused features that accept complex input.
• Ensure the underlying operating system and web-server stack are also current, because ColdFusion often runs with elevated privileges.
• Re-test authentication, input validation, and network exposure after the update to confirm the remediation did not introduce configuration regressions.

If you can't patch immediately

Until the vendor update can be applied, reduce exposure with compensating controls appropriate to a remote-code-execution deserialization flaw:

• Segment ColdFusion hosts onto isolated network zones; block inbound access from untrusted networks and limit outbound connectivity to only required destinations.
• Place a web application firewall (WAF) or reverse-proxy filter in front of ColdFusion and enable rules that inspect or block requests containing serialized object streams or known malicious patterns for this product class; treat these as virtual patches and tune them carefully to avoid false positives.
• Disable or restrict any ColdFusion features, endpoints, or administrative interfaces that are not strictly required for business operations.
• Increase monitoring and alerting on the ColdFusion process, its log files, and the host’s process-creation events so that anomalous activity can be investigated quickly.
• If feasible, temporarily take non-critical ColdFusion instances offline or place them behind additional authentication gateways.

These measures lower risk but do not eliminate it; schedule the official patch as soon as operational constraints allow.

If your data may have been exposed

Vulnerabilities that enable remote code execution are frequently leveraged in breaches. If your ColdFusion environment was reachable and unpatched during the period of exposure, assume an attacker could have obtained code execution and potentially accessed data processed by the application. Review system and application logs for indicators of compromise, rotate credentials that may have been present on the host, and follow your incident-response plan. As an additional step, individuals can run a free exposure scan of their email address to check whether that address appears in known breach data sets.