CVE-2026-21008: Samsung Android Information Disclosure Flaw

CVE-2026-21008 Overview

CVE-2026-21008 is a sensitive information exposure vulnerability in Samsung's S Share application on Android devices. This vulnerability allows an attacker on an adjacent network to access sensitive information without requiring authentication. The flaw exists in versions of S Share prior to the Samsung Mobile Release (SMR) April 2026 Release 1 and affects Samsung Android versions 14.0, 15.0, and 16.0.

Critical Impact

Adjacent network attackers can access sensitive information from vulnerable Samsung devices running S Share without authentication, potentially exposing private user data during file sharing operations.

Affected Products

• Samsung Android 14.0 (all SMR versions prior to Apr-2026 Release 1)
• Samsung Android 15.0 (all SMR versions prior to Apr-2026 Release 1)
• Samsung Android 16.0 (all SMR versions prior to Apr-2026 Release 1)

Discovery Timeline

• April 13, 2026 - CVE-2026-21008 published to NVD
• April 13, 2026 - Last updated in NVD database

Technical Details for CVE-2026-21008

Vulnerability Analysis

This vulnerability is classified as an information exposure issue within the S Share application, which is Samsung's file sharing feature for transferring files between nearby devices. The vulnerability allows an attacker positioned on an adjacent network (such as the same Wi-Fi network or within Bluetooth range) to intercept or access sensitive information during S Share operations.

The attack requires user interaction, indicating that a victim must perform a specific action (such as initiating a file share) for the vulnerability to be exploited. While the attacker does not need any special privileges or authentication, physical or network proximity is required, limiting the attack surface compared to remote network-based attacks.

The confidentiality impact is limited, meaning some restricted information may be exposed but not all data processed by the application. There is no impact on data integrity or system availability, making this primarily a data disclosure issue rather than a system compromise vulnerability.

Root Cause

The root cause involves improper handling of sensitive information within the S Share application's communication protocols. While specific technical details have not been publicly disclosed by Samsung, information exposure vulnerabilities in file sharing applications typically stem from insufficient encryption of data in transit, improper access controls on shared resources, or metadata leakage during the discovery or pairing process.

Attack Vector

The attack vector requires the adversary to be on an adjacent network, which includes scenarios such as:

• Being connected to the same Wi-Fi network as the victim
• Being within Bluetooth or Wi-Fi Direct range
• Having access to the same local network segment

The attacker can then monitor S Share communications or intercept data being transmitted during file sharing operations. User interaction is required, meaning the victim must actively use the S Share feature for the vulnerability to be exploitable.

The vulnerability mechanism exploits the adjacent network communication channels used by S Share. An attacker positioned on the same network segment can intercept or access sensitive data transmitted during file sharing operations due to insufficient protection of the communication channel or improper access controls. For detailed technical information, refer to the Samsung Security Update April 2026.

Detection Methods for CVE-2026-21008

Indicators of Compromise

• Unusual network traffic patterns on Wi-Fi or Bluetooth interfaces associated with S Share service
• Unexpected connection attempts to S Share service from unknown devices on the local network
• Anomalous data transfer activities involving the S Share application when not intentionally initiated by the user

Detection Strategies

• Monitor Android system logs for unusual S Share activity or connection attempts from unrecognized devices
• Implement network monitoring to detect suspicious adjacent network scanning or discovery probes targeting Samsung device services
• Deploy mobile threat detection solutions that can identify abnormal application behavior or unauthorized data access attempts

Monitoring Recommendations

• Enable verbose logging on managed Samsung devices to capture S Share connection events
• Utilize Mobile Device Management (MDM) solutions to monitor application behavior and network connections
• Configure alerts for unusual file sharing activity patterns across the enterprise device fleet

How to Mitigate CVE-2026-21008

Immediate Actions Required

• Update all Samsung Android devices to the SMR April 2026 Release 1 or later
• Disable S Share functionality on devices that cannot be immediately updated
• Advise users to avoid using S Share on untrusted networks until the patch is applied
• Review and restrict S Share usage policies in enterprise environments

Patch Information

Samsung has released a security patch addressing this vulnerability in the SMR April 2026 Release 1. Organizations and users should apply this update as soon as possible through their device's Software Update settings or via MDM deployment.

Detailed patch information is available in the Samsung Security Update April 2026.

Workarounds

• Disable S Share functionality in device settings until the patch can be applied
• Use alternative file transfer methods that employ end-to-end encryption
• Avoid using S Share on public or untrusted Wi-Fi networks
• Enable strict pairing requirements and verification for file sharing operations

# Check current Samsung software version via ADB
adb shell getprop ro.build.version.security_patch
# Expected output for patched devices: 2026-04-01 or later