CVE-2026-48376: Adobe ColdFusion Auth Bypass Vulnerability

CVE-2026-48376 Overview

Adobe ColdFusion contains an Improper Encoding or Escaping of Output vulnerability [CWE-116] that allows a security feature bypass. A low-privileged, authenticated attacker can exploit the flaw across the network without user interaction. Successful exploitation grants limited unauthorized write access and causes limited disruption to availability, but does not expose confidential data.

The issue affects Adobe ColdFusion 2023 (base release through Update 22) and Adobe ColdFusion 2025 (base release through Update 11). Adobe published security bulletin APSB26-90 to address the vulnerability. Administrators running affected ColdFusion versions should apply the vendor updates promptly to restore intended output encoding and escaping behavior.

Critical Impact
An authenticated attacker with low privileges can bypass built-in security controls remotely to write unauthorized data and disrupt service availability on affected ColdFusion servers.

Affected Products

Adobe ColdFusion 2023 (base release through Update 22)
Adobe ColdFusion 2025 (base release through Update 11)
Web applications and APIs deployed on the affected ColdFusion runtime

Discovery Timeline

2026-08-11 - CVE-2026-48376 published to the National Vulnerability Database
2026-08-13 - Last updated in NVD database

Technical Details for CVE-2026-48376

Vulnerability Analysis

The vulnerability stems from improper encoding or escaping of output within Adobe ColdFusion. Under [CWE-116], the software prepares structured output for downstream components but fails to neutralize or correctly encode characters that carry special meaning in the target context. When the output reaches its consumer, the unescaped characters alter parsing and control flow rather than being treated as inert data.

In ColdFusion, this class of defect can subvert security features that rely on trusted input representation. An authenticated attacker with low privileges can craft payloads whose encoding sidesteps validation or sanitization checks. The consequence is limited unauthorized write access and limited disruption to availability, without direct disclosure of confidential information.

Exploitation is remote and requires no user interaction, which raises the risk profile for internet-exposed ColdFusion instances. Because the scope is unchanged, the impact remains within the vulnerable component itself.

Root Cause

The root cause is inconsistent or missing output encoding in code paths that pass data to security-relevant consumers. When special characters are not neutralized for the downstream parser, they escape their intended context and change the meaning of the transmitted structure. This allows a caller to bypass checks that assume properly encoded input.

Attack Vector

The attack vector is network-based against the ColdFusion service. An attacker authenticates with low privileges and submits a request containing crafted payload data whose encoding evades the affected security control. No user interaction is needed to complete the bypass, and the request can originate from any host with network reachability to the target.

No public proof-of-concept exploit is currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Technical specifics are limited to the vendor advisory. See the Adobe ColdFusion Security Advisory APSB26-90 for authoritative details.

Detection Methods for CVE-2026-48376

Indicators of Compromise

Unexpected write operations on ColdFusion application data stores or file paths performed by low-privileged application accounts.
HTTP requests containing unusual encoding sequences, mixed URL/HTML/Unicode escapes, or double-encoded payloads directed at ColdFusion endpoints.
Authenticated session activity that touches administrative or security-controlled functions outside the account's normal usage pattern.

Detection Strategies

Inspect ColdFusion access and application logs for repeated requests from a single authenticated identity that trigger encoding-related errors or 4xx/5xx anomalies.
Correlate authentication events with subsequent write actions to identify low-privileged accounts performing operations reserved for higher roles.
Deploy web application firewall rules that decode requests recursively and flag payloads that change meaning after normalization.

Monitoring Recommendations

Forward ColdFusion server, application, and WAF logs to a centralized analytics platform for correlation across identities, sessions, and hosts.
Baseline normal request encodings per endpoint and alert on statistically rare encoding patterns targeting security-sensitive handlers.
Monitor file system and database writes originating from the ColdFusion service account for changes outside expected directories or tables.

How to Mitigate CVE-2026-48376

Immediate Actions Required

Apply the Adobe ColdFusion security updates referenced in APSB26-90 to ColdFusion 2023 and ColdFusion 2025 installations.
Inventory all internet-exposed ColdFusion instances and prioritize patching on those reachable from untrusted networks.
Review authentication logs for low-privileged accounts and rotate credentials that show anomalous activity.

Patch Information

Adobe addressed the vulnerability in the updates published with security bulletin APSB26-90. Administrators should upgrade Adobe ColdFusion 2023 and Adobe ColdFusion 2025 to the fixed update levels listed in the advisory. Follow Adobe's documented upgrade procedure and validate application functionality in a staging environment before production rollout.

Workarounds

Restrict network access to ColdFusion administrative and application endpoints using firewall rules or reverse-proxy allowlists until patches are applied.
Enforce strict input validation and output encoding in custom ColdFusion code that handles user-supplied data passed to security-relevant sinks.
Reduce the privilege of ColdFusion application accounts to the minimum required, limiting the blast radius of a successful bypass.

bash

# Configuration example: restrict ColdFusion admin access at the reverse proxy
# nginx example — allow only trusted management network
location /CFIDE/administrator/ {
    allow 10.10.20.0/24;
    deny all;
    proxy_pass http://coldfusion_backend;
}