CVE-2026-21137 Overview
CVE-2026-21137 is a path traversal vulnerability [CWE-22] affecting Samsung Smart Switch prior to version 3.7.73. The flaw allows a physical attacker to access files with Smart Switch privileges on the device. Samsung disclosed the issue through its October 2026 Mobile Security Update bulletin.
The vulnerability requires physical access to the target device. Exploitation does not require authentication or user interaction, but the attack vector is constrained to local, hands-on scenarios such as lost, stolen, or temporarily unattended devices.
Critical Impact
A physical attacker can traverse directory paths to read files accessible to the Smart Switch application, exposing confidentiality of data within the app's privilege scope.
Affected Products
- Samsung Smart Switch versions prior to 3.7.73
- Mobile devices with vulnerable Smart Switch installations
- Devices synchronizing data via Smart Switch transfer flows
Discovery Timeline
- 2026-10-12 - CVE-2026-21137 published to NVD
- 2026-10-14 - Last updated in NVD database
Technical Details for CVE-2026-21137
Vulnerability Analysis
Smart Switch is Samsung's data migration utility used to transfer contacts, media, settings, and application data between mobile devices. The vulnerability resides in how the application resolves file paths during transfer or restore operations.
An attacker with physical access can supply crafted path strings containing traversal sequences such as ../ to escape the intended working directory. Successful traversal returns files that reside outside the Smart Switch sandbox but remain readable under its process privileges.
Because Smart Switch runs with elevated access to user data to support backup and restore, the files reachable through the traversal may include sensitive application artifacts, cached credentials, or configuration data stored on the device.
Root Cause
The root cause is improper limitation of a pathname to a restricted directory [CWE-22]. Smart Switch does not sufficiently normalize or validate user-controlled file path components before opening files, allowing .. segments to resolve outside the intended base directory.
Attack Vector
Exploitation requires physical access to an unlocked device or to transfer interfaces exposed by Smart Switch. The attacker interacts with the local attack surface rather than any network service, which limits remote exploitation but still produces a meaningful risk for lost or stolen hardware.
No verified public proof-of-concept is available. Samsung's advisory is the authoritative source for technical details. See the Samsung Mobile Security Update for vendor guidance.
Detection Methods for CVE-2026-21137
Indicators of Compromise
- Smart Switch application logs showing file access attempts containing .., %2e%2e, or encoded path separators
- Unexpected read operations against directories outside the Smart Switch working path
- Evidence of Smart Switch sessions initiated during periods when the device was unattended
Detection Strategies
- Audit mobile device management (MDM) inventory for devices running Smart Switch versions below 3.7.73
- Review device access logs for Smart Switch activity correlated with physical custody gaps
- Monitor for anomalous file reads originating from the Smart Switch process on managed endpoints
Monitoring Recommendations
- Enroll Samsung mobile devices in an MDM solution capable of enforcing application version baselines
- Alert when Smart Switch is launched outside approved migration workflows
- Track physical device custody events, including loss, theft, or repair handoffs
How to Mitigate CVE-2026-21137
Immediate Actions Required
- Update Samsung Smart Switch to version 3.7.73 or later on all managed mobile devices
- Enforce device lock screens with strong authentication to reduce physical attack opportunities
- Disable Smart Switch transfer modes when not actively migrating data
Patch Information
Samsung addressed CVE-2026-21137 in Smart Switch version 3.7.73. Patch details and distribution are published in the Samsung Mobile Security Update bulletin for October 2026. Update through the Galaxy Store or vendor-approved distribution channels.
Workarounds
- Restrict physical access to Samsung mobile devices storing sensitive data
- Uninstall Smart Switch on devices where data migration functionality is not required
- Require full-disk encryption and short screen-lock timeouts on affected handsets
# Verify installed Smart Switch version on a connected Samsung device via ADB
adb shell dumpsys package com.sec.android.easyMover | grep versionName
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
