CVE-2026-34633: ColdFusion SSRF Privilege Escalation Flaw

CVE-2026-34633 Overview

CVE-2026-34633 is a Server-Side Request Forgery (SSRF) vulnerability affecting Adobe ColdFusion. A low-privileged attacker can abuse the flaw to force the ColdFusion server to issue attacker-controlled requests to internal resources. Successful exploitation results in privilege escalation and does not require user interaction. The CVSS vector indicates a scope change, meaning the impact extends beyond the vulnerable component to adjacent systems reachable from the ColdFusion host.

Critical Impact
An authenticated low-privileged attacker can pivot through the ColdFusion server to access protected internal services and escalate privileges across trust boundaries.

Affected Products

Adobe ColdFusion (versions enumerated in Adobe advisory APSB26-144)
ColdFusion deployments exposing authenticated low-privileged accounts
Server environments where ColdFusion has network access to internal resources

Discovery Timeline

2026-10-13 - CVE-2026-34633 published to the National Vulnerability Database (NVD)
2026-10-14 - Last updated in NVD database

Technical Details for CVE-2026-34633

Vulnerability Analysis

The vulnerability is classified under CWE-918: Server-Side Request Forgery (SSRF). ColdFusion processes user-supplied input that influences the destination of a server-initiated HTTP or network request. The server fails to validate or restrict that destination to an allowlist of safe targets.

An attacker who holds any low-privileged account on the ColdFusion instance can submit crafted input that coerces the server into contacting internal resources. Because the request originates from the ColdFusion host, it inherits that host's network position and trust relationships. The scope change in the CVSS vector reflects that the compromised component (ColdFusion) is used to affect a different security authority, such as internal metadata services, administrative endpoints, or backend APIs.

Root Cause

The root cause is insufficient validation of user-controllable URLs or network destinations consumed by a ColdFusion request-issuing function. The server treats attacker-influenced input as a trusted request target, bypassing network segmentation and authentication boundaries that normally protect internal services.

Attack Vector

Exploitation occurs over the network and requires low privileges but no user interaction. An attacker authenticates with a low-privileged account, then submits a request containing a crafted URL pointing to an internal resource. ColdFusion issues the outbound request on behalf of the attacker and may return response data, enabling access to cloud instance metadata endpoints, internal administrative interfaces, or services otherwise unreachable from the public network. Access to these endpoints can be chained to retrieve credentials or configuration data, resulting in privilege escalation.

See the Adobe ColdFusion Security Advisory (APSB26-144) for vendor-confirmed technical details.

Detection Methods for CVE-2026-34633

Indicators of Compromise

Outbound HTTP requests from the ColdFusion server to internal IP ranges (RFC1918), loopback addresses, or cloud metadata endpoints such as 169.254.169.254
ColdFusion application logs containing URL parameters pointing to internal hostnames, link-local addresses, or non-standard ports
Authentication events from low-privileged ColdFusion accounts followed by anomalous outbound connections
Unexpected access patterns to internal administrative interfaces originating from the ColdFusion host

Detection Strategies

Inspect ColdFusion request logs for user-supplied parameters that contain URLs, IP addresses, or hostnames
Correlate authenticated session activity from low-privileged users with outbound network connections initiated by the ColdFusion process
Alert on ColdFusion-originated DNS lookups for internal domains or cloud metadata hostnames

Monitoring Recommendations

Enable verbose logging for ColdFusion HTTP client functions and track destination hosts
Deploy egress filtering at the network layer and alert on blocked outbound requests from application servers
Monitor cloud metadata service access logs where ColdFusion runs on AWS, Azure, or GCP instances

How to Mitigate CVE-2026-34633

Immediate Actions Required

Apply the security updates referenced in Adobe advisory APSB26-144 to all ColdFusion installations
Audit all low-privileged ColdFusion accounts and disable those that are unused or unnecessary
Restrict ColdFusion server egress to only required external destinations using network ACLs or host firewalls
Enforce Instance Metadata Service Version 2 (IMDSv2) on cloud-hosted ColdFusion instances to require session tokens for metadata access

Patch Information

Adobe published fixes for CVE-2026-34633 as part of security bulletin APSB26-144. Administrators should consult the Adobe ColdFusion Security Advisory for the exact patched version numbers and apply updates to all affected ColdFusion instances.

Workarounds

Block ColdFusion outbound access to internal subnets, loopback addresses, and cloud metadata endpoints at the network perimeter
Place ColdFusion behind a forward proxy that enforces an allowlist of permitted outbound destinations
Restrict access to the ColdFusion administrator and user-authenticated application paths with network-layer controls until patching is complete

bash

# Example egress restriction using iptables to block cloud metadata access
iptables -A OUTPUT -m owner --uid-owner coldfusion -d 169.254.169.254 -j DROP
iptables -A OUTPUT -m owner --uid-owner coldfusion -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -m owner --uid-owner coldfusion -d 172.16.0.0/12 -j DROP
iptables -A OUTPUT -m owner --uid-owner coldfusion -d 192.168.0.0/16 -j DROP