CVE-2026-56578: HCL MyCloud Information Disclosure Flaw

CVE-2026-56578 Overview

CVE-2026-56578 is an information disclosure vulnerability affecting HCL MyCloud version 10.8.1. The application exposes server version details in its responses, allowing authenticated users with high privileges to identify the underlying software versions in use. Attackers can use this information to map the environment against public vulnerability databases and select known exploits targeting the disclosed versions. The vulnerability is classified under [CWE-200] (Exposure of Sensitive Information to an Unauthorized Actor). While the direct impact is limited, version disclosure is a common reconnaissance primitive that supports later stages of an attack chain.

Critical Impact

Server version disclosure in HCL MyCloud enables attackers to fingerprint the deployment and target it with known exploits for the identified software versions.

Affected Products

• HCL MyCloud 10.8.1
• Vendor: HCL Technologies (hcltech)
• Product component: hcltech:mycloud

Discovery Timeline

• 2026-07-21 - CVE-2026-56578 published to NVD
• 2026-07-22 - Last updated in NVD database

Technical Details for CVE-2026-56578

Vulnerability Analysis

CVE-2026-56578 is an information disclosure issue in HCL MyCloud 10.8.1. The application returns server software version information within its responses. This behavior falls under [CWE-200], where a system exposes technical data that should remain internal. The exposure itself does not compromise data confidentiality of user records, integrity, or availability. Its value is reconnaissance. An attacker who obtains the exact server version can cross-reference it with vulnerability databases and select matching exploits. The CVSS vector indicates a network attack path but requires high privileges and high attack complexity, which limits opportunistic exploitation.

Root Cause

The root cause is verbose server response metadata. HCL MyCloud emits software version identifiers in headers, error messages, or banner responses without stripping or normalizing them. Applications that echo build and version data give attackers a precise fingerprint of the runtime stack. Secure defaults require suppressing or generalizing this information at the application and reverse-proxy layer.

Attack Vector

An authenticated attacker with high privileges interacts with the MyCloud instance over the network. The attacker observes responses that contain server version strings. The disclosed values are then correlated with known CVEs affecting the specific version. No exploit code is publicly available at time of publication, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS score reflects a low probability of active exploitation.

See the HCL Software Knowledge Base Article for vendor-provided technical details.

Detection Methods for CVE-2026-56578

Indicators of Compromise

• HTTP responses from MyCloud endpoints containing explicit Server or X-Powered-By headers revealing product version strings.
• Application error pages or API responses that include internal build identifiers or component versions.
• Repeated authenticated probes from a single account against version-revealing endpoints.

Detection Strategies

• Inspect outbound HTTP responses from MyCloud 10.8.1 for headers or body content containing version identifiers.
• Correlate authenticated session activity with unusual reconnaissance patterns such as repeated requests to diagnostic or status endpoints.
• Baseline normal administrative traffic and alert on high-privilege accounts issuing bulk metadata queries.

Monitoring Recommendations

• Enable request and response logging at the reverse proxy or WAF fronting MyCloud.
• Retain authentication logs for high-privilege accounts and review for anomalous access patterns.
• Monitor threat intelligence feeds for new exploits targeting HCL MyCloud versions in your environment.

How to Mitigate CVE-2026-56578

Immediate Actions Required

• Review the HCL Software Knowledge Base Article and apply the vendor's guidance for HCL MyCloud 10.8.1.
• Audit accounts with high privileges on MyCloud and remove entitlements that are not required.
• Restrict network access to the MyCloud management interfaces to trusted administrative networks.

Patch Information

Refer to the HCL Software Knowledge Base Article KB0132381 for official remediation guidance from HCL. Apply the vendor-supplied fix or configuration change for HCL MyCloud 10.8.1 as directed.

Workarounds

• Configure a reverse proxy or WAF to strip Server, X-Powered-By, and other version-revealing headers from HCL MyCloud responses.
• Replace verbose application error pages with generic messages that do not disclose stack or build information.
• Limit exposure of administrative endpoints to segmented networks and enforce strong access controls on high-privilege accounts.

# Example: strip version headers at an Nginx reverse proxy fronting HCL MyCloud
server {
    listen 443 ssl;
    server_name mycloud.example.com;

    proxy_hide_header Server;
    proxy_hide_header X-Powered-By;
    proxy_hide_header X-AspNet-Version;

    location / {
        proxy_pass https://mycloud-backend.internal;
        proxy_set_header Host $host;
    }

    error_page 500 502 503 504 /generic_error.html;
}