CVE-2026-21791: HCL Sametime Android Info Disclosure Flaw

CVE-2026-21791 Overview

HCL Sametime for Android is impacted by a sensitive information disclosure vulnerability where hostnames information is written to application logs and certain URLs. This vulnerability (CWE-532: Insertion of Sensitive Information into Log File) allows attackers with local access to potentially extract sensitive hostname and server configuration data from application logs.

Critical Impact

Sensitive hostname information exposed in application logs and URLs could be leveraged by attackers to map internal network infrastructure and facilitate further attacks.

Affected Products

• HCL Sametime for Android

Discovery Timeline

• 2026-03-10 - CVE-2026-21791 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2026-21791

Vulnerability Analysis

This vulnerability belongs to the CWE-532 category (Insertion of Sensitive Information into Log File), a common mobile application security weakness. The HCL Sametime Android application improperly logs sensitive hostname information, which can be accessed by other applications or users with sufficient device privileges.

Android applications that write sensitive data to system logs create a security risk because these logs can be accessed through various means on rooted devices or by applications with the READ_LOGS permission. In this case, the exposed hostname information could reveal internal server names, IP addresses, or enterprise infrastructure details that attackers could use for reconnaissance.

The local attack vector means an attacker would need some level of access to the device, either physical access or through another compromised application. While the direct impact is limited to information disclosure affecting confidentiality, this leaked information could serve as a stepping stone for more sophisticated attacks against the organization's infrastructure.

Root Cause

The root cause is improper logging practices in the HCL Sametime Android application. The application writes hostnames and potentially sensitive URL information to application logs without proper sanitization or log level controls. This violates secure coding principles that dictate sensitive information should never be written to logs, especially in production builds.

Attack Vector

An attacker with local access to the Android device can exploit this vulnerability through the following approach:

1. Gain access to the target device (physical access, ADB debugging, or through another malicious app)
2. Access application logs via logcat or by reading log files directly on rooted devices
3. Extract hostname and URL information from the logs
4. Use the gathered intelligence to map internal infrastructure or plan targeted attacks

The attack requires local access and low privileges, making it most relevant in scenarios involving device theft, insider threats, or compromised devices with malicious applications installed.

Detection Methods for CVE-2026-21791

Indicators of Compromise

• Unusual access patterns to application log files or directories
• Multiple logcat command executions from unexpected processes
• Evidence of ADB debugging enabled on production devices
• Unauthorized applications with READ_LOGS permission installed on devices

Detection Strategies

• Monitor for attempts to access HCL Sametime log files from unauthorized processes
• Implement Mobile Device Management (MDM) policies to detect rooted devices
• Review application permissions for apps requesting READ_LOGS or similar sensitive permissions
• Enable audit logging for ADB connections on managed Android devices

Monitoring Recommendations

• Deploy endpoint detection capabilities on mobile devices to identify suspicious log access
• Implement application-level logging controls and monitoring
• Use SentinelOne Mobile Threat Defense to detect anomalous application behavior
• Review and restrict which applications have access to device logs through MDM policies

How to Mitigate CVE-2026-21791

Immediate Actions Required

• Review the HCL Software Knowledge Base Article for vendor guidance
• Update HCL Sametime for Android to the latest available version
• Audit devices for evidence of unauthorized log access
• Ensure devices are not rooted and have proper security policies enforced

Patch Information

HCL has released information regarding this vulnerability. Organizations should consult the official HCL Software Knowledge Base Article for specific patch details and updated application versions that address this information disclosure issue.

Workarounds

• Disable ADB debugging on production devices using MDM policies
• Implement application log rotation and automatic deletion to minimize exposure window
• Restrict installation of applications that request log access permissions
• Consider deploying network segmentation to limit the value of exposed hostname information
• Use SentinelOne Mobile Threat Defense to monitor for suspicious activity on managed devices