CVE-2026-21063 Overview
CVE-2026-21063 is a medium-severity vulnerability in Samsung's AppLock feature on Android devices. The flaw results from improper export of Android application components [CWE-926], allowing a physical attacker to bypass the app lock function. Samsung addressed the issue in the SMR Aug-2026 Release 1 security maintenance update.
The vulnerability requires physical access to an unlocked-adjacent device state and no user interaction. Successful exploitation compromises the confidentiality and integrity of applications that users protected behind AppLock, exposing sensitive data such as messages, banking apps, or photos.
Critical Impact
A physical attacker can bypass Samsung AppLock protection and access confidential data inside apps the user explicitly chose to shield.
Affected Products
- Samsung Android devices running builds prior to SMR Aug-2026 Release 1
- Samsung AppLock component
- Devices dependent on Samsung's monthly Security Maintenance Release (SMR) cycle
Discovery Timeline
- 2026-08-10 - CVE-2026-21063 published to NVD
- 2026-08-10 - Samsung publishes SMR Aug-2026 Release 1 addressing the issue
- 2026-08-10 - Last updated in NVD database
Technical Details for CVE-2026-21063
Vulnerability Analysis
Samsung AppLock lets users require an additional authentication factor, such as a PIN or biometric, before opening selected applications. The feature works by intercepting activity launches and prompting the user for credentials before the target app becomes visible.
The vulnerability stems from improperly exported Android application components within the AppLock implementation. Android components declared with android:exported="true" or with an implicit intent filter become reachable from other apps and from the adb shell. When AppLock exports internal components that should remain private, an attacker with physical access can invoke those components directly and skip the authentication prompt.
Because the attack occurs at the component-invocation layer, the target application can be launched in a state where AppLock never enforces its check. The bypass does not require credential theft, exploit chains, or privileged code execution on the device.
Root Cause
The root cause is a manifest and component-visibility error classified as [CWE-926] Improper Export of Android Application Components. Sensitive AppLock activities, services, or broadcast receivers are exposed to other callers on the device without adequate permission enforcement or caller validation.
Attack Vector
Exploitation requires physical access to the target device. An attacker with adb access, a companion application, or an app installed by the victim can issue an intent that targets the exported AppLock component and reaches the protected activity while bypassing the lock screen prompt.
The vulnerability does not enable remote exploitation, does not require user interaction, and does not require prior privileges on the device. Samsung has not confirmed exploitation in the wild, and no public proof-of-concept is available.
Detection Methods for CVE-2026-21063
Indicators of Compromise
- Unexpected adb connections or developer-mode enablement on managed Samsung devices
- Launches of AppLock-protected applications without a corresponding successful authentication event in system logs
- Installation of unknown third-party applications that request the ability to launch other apps via intents
Detection Strategies
- Correlate AppLock authentication events with subsequent activity launches; missing authentication before a protected app opens indicates bypass attempts
- Alert on mobile device management (MDM) telemetry showing USB debugging enabled outside approved change windows
- Monitor for the presence of Samsung devices reporting a security patch level older than SMR Aug-2026 Release 1
Monitoring Recommendations
- Ingest Samsung Knox and MDM logs into a centralized SIEM to track patch level and developer-option changes across the fleet
- Flag devices where physical tamper indicators, such as unlocked bootloaders or new USB-host activity, appear
- Review enterprise application inventories for apps requesting broad QUERY_ALL_PACKAGES or intent-forwarding capabilities
How to Mitigate CVE-2026-21063
Immediate Actions Required
- Deploy the Samsung SMR Aug-2026 Release 1 update to all affected devices through your MDM or user-driven update workflow
- Verify the applied security patch level on each managed device and quarantine devices that cannot be updated
- Disable USB debugging and OEM unlocking by policy on enterprise-managed Samsung devices
Patch Information
Samsung published the fix in the SMR Aug-2026 Release 1 security maintenance release. Full advisory details are available in the Samsung Security Update August 2026 bulletin. Confirm devices show a security patch level dated August 2026 or later after applying the update.
Workarounds
- Enforce strong device-level screen lock policies so physical access to an unlocked device is minimized
- Require full-device encryption and short screen-lock timeouts through MDM configuration profiles
- Restrict physical access to corporate mobile devices and revoke access for devices reported lost or stolen
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
