CVE-2026-21766: HCL DX Information Disclosure Vulnerability

CVE-2026-21766 Overview

CVE-2026-21766 affects the default login portlet in HCL Digital Experience and HCL Digital Experience Compose. The portlet insufficiently protects credentials during authentication processing. Under specific configurations and use cases, sensitive credential information may be written to web server log files.

The issue only impacts deployments that rely on the default login portlet. Custom login implementations are not affected. The weakness is classified as [CWE-522] Insufficiently Protected Credentials.

Attackers with access to web server logs can extract credentials from log entries. This exposure enables downstream account takeover and lateral movement within HCL Digital Experience environments.

Critical Impact
Credentials submitted through the default login portlet can be recorded in web server logs, exposing them to any user or process with log-read access.

Affected Products

HCL Digital Experience (default login portlet)
HCL Digital Experience Compose (default login portlet)
Deployments using default authentication configuration

Discovery Timeline

2026-08-05 - CVE-2026-21766 published to NVD
2026-08-05 - Last updated in NVD database

Technical Details for CVE-2026-21766

Vulnerability Analysis

The default login portlet in HCL Digital Experience handles user authentication requests through standard portal servlet infrastructure. During request processing, the portlet fails to consistently sanitize authentication parameters before they reach diagnostic and access logging subsystems.

Under specific configuration states, credential fields flow into log output. Web server access logs, portal trace logs, or diagnostic captures can then persist plaintext or partially protected credentials on disk. The exposure requires a narrow combination of runtime settings, which raises exploitation complexity but does not eliminate risk.

Exploitation requires high privileges and user interaction, and the scope is changed because credentials written to logs can be accessed by components outside the portlet's authority boundary. Confidentiality impact is high; integrity and availability are not affected.

Root Cause

The root cause is improper handling of sensitive form parameters within the default login portlet's request pipeline. Authentication field values are not filtered from logging paths under all supported configurations, violating credential protection expectations described in [CWE-522].

Attack Vector

An attacker with read access to web server logs, log aggregation systems, or backup archives can harvest captured credentials. Access to logs may be obtained through compromised administrator accounts, misconfigured log shipping, or exposed log storage. Credentials extracted from logs then permit authenticated access to the portal.

No synthetic exploitation code is provided. Refer to the HCL Software Knowledge Base Article for vendor-supplied technical detail.

Detection Methods for CVE-2026-21766

Indicators of Compromise

Web server access or trace logs containing values in login form parameter fields such as username, password, j_password, or wps.portlets.userid.
Unexpected log entries referencing the default login portlet with populated POST body content.
Access to portal log files from accounts or processes outside standard administrative workflows.

Detection Strategies

Scan existing HCL Digital Experience log archives for credential-like patterns tied to the login portlet URL path.
Correlate portal authentication events with subsequent log-file read events on the hosting server.
Alert on anomalous access to /logs, wp_profile log directories, or backup shares containing portal logs.

Monitoring Recommendations

Enable file integrity monitoring on portal log directories and restrict read permissions to a minimal service account set.
Ingest web server and portal logs into a SIEM and apply regular expressions that identify credential leakage patterns.
Track successful logins that follow log-read events from non-standard identities as potential credential replay.

How to Mitigate CVE-2026-21766

Immediate Actions Required

Apply the vendor guidance published in the HCL Software Knowledge Base Article.
Rotate credentials for any accounts that authenticated through the default login portlet while the vulnerable configuration was active.
Purge or securely archive historical web server logs that may contain captured credentials.
Restrict read access to portal and web server log directories to essential administrators only.

Patch Information

HCL Software has published remediation guidance through its knowledge base. Administrators should consult the HCL Software Knowledge Base Article KB0132659 for supported fix versions and configuration changes applicable to HCL Digital Experience and HCL Digital Experience Compose.

Workarounds

Replace the default login portlet with a custom authentication portlet that explicitly excludes credential fields from logging.
Adjust web server and application server log configurations to suppress POST body capture on the login endpoint.
Enforce log redaction pipelines that strip parameters matching credential field names before storage.

bash

# Configuration example - restrict access to portal log directories
chown -R wasadmin:wasadmin /opt/HCL/wp_profile/logs
chmod -R 640 /opt/HCL/wp_profile/logs
find /opt/HCL/wp_profile/logs -type d -exec chmod 750 {} \;