CVE-2026-21052 Overview
CVE-2026-21052 is a path traversal vulnerability in Samsung's SemClipboardService component on Samsung mobile devices. The flaw allows local attackers with existing privileges to traverse directory paths and access files that should be restricted to the system user. Samsung addressed the issue in the SMR Jul-2026 Release 1 security maintenance release.
The vulnerability enables local privilege escalation on affected Samsung devices by leveraging the clipboard service's file handling logic. Successful exploitation grants an attacker read access to files running under system privilege, exposing sensitive device data.
Critical Impact
Local privileged attackers can access system-level files on Samsung mobile devices running versions prior to SMR Jul-2026 Release 1.
Affected Products
- Samsung Mobile devices with SemClipboardService prior to SMR Jul-2026 Release 1
- Samsung Android-based smartphones and tablets shipped with Samsung Experience/One UI
- Devices not yet updated with the July 2026 Samsung Mobile Security Maintenance Release
Discovery Timeline
- 2026-07-10 - CVE-2026-21052 published to NVD
- 2026-07-14 - Last updated in NVD database
Technical Details for CVE-2026-21052
Vulnerability Analysis
The vulnerability resides in SemClipboardService, a Samsung-specific extension of the Android clipboard framework. The service handles clipboard data operations, including reading and writing files referenced by clipboard content. The service fails to sanitize file path inputs before performing file system operations.
Because SemClipboardService runs with system privileges, a local attacker who already possesses some privilege level can supply crafted path strings containing traversal sequences. The service then resolves these paths and reads files outside the intended clipboard sandbox. This class of flaw is classified as Path Traversal [CWE-22].
The attack requires local access and existing privileges on the device, limiting remote exploitation. The impact is scoped to confidentiality, with no integrity or availability effect. The EPSS score of 0.131% reflects a low probability of exploitation activity in the wild at the time of publication.
Root Cause
The root cause is missing or insufficient validation of file path parameters passed to SemClipboardService. The service accepts path input from lower-privileged callers and resolves it directly against the file system without canonicalization or containment checks. Sequences such as ../ are not stripped or rejected before the file open operation.
Attack Vector
Exploitation requires a local attacker with existing privileges on the target device, such as an installed application with limited permissions or an ADB-connected user. The attacker invokes SemClipboardService with a crafted file path containing directory traversal sequences. The service, running as system, resolves the path and returns file contents that the calling process could not otherwise access.
The vulnerability manifests through the clipboard service's inter-process communication interface. Refer to the Samsung Mobile Security Update for vendor-specific technical details.
Detection Methods for CVE-2026-21052
Indicators of Compromise
- Applications invoking SemClipboardService with file path arguments containing ../ or absolute paths outside expected clipboard directories
- Unexpected file access events attributed to the system user originating from clipboard service IPC calls
- Installed applications requesting clipboard-related permissions without a legitimate business justification
Detection Strategies
- Monitor Android logcat and audit logs for SemClipboardService calls with suspicious path parameters
- Review installed application manifests for unusual clipboard service bindings on unpatched devices
- Correlate file access events under system UID with clipboard service process activity to identify traversal attempts
Monitoring Recommendations
- Track device patch level (ro.build.version.security_patch) across the mobile fleet to identify devices running versions prior to SMR Jul-2026 Release 1
- Enable mobile threat defense telemetry to flag applications performing anomalous IPC against system services
- Alert on newly installed applications on unpatched Samsung devices that request clipboard-related interactions
How to Mitigate CVE-2026-21052
Immediate Actions Required
- Apply the Samsung SMR Jul-2026 Release 1 security maintenance release to all affected Samsung mobile devices
- Inventory Samsung devices in the fleet and prioritize patch deployment for devices holding sensitive corporate data
- Restrict installation of untrusted applications on unpatched devices through mobile device management (MDM) policies
Patch Information
Samsung released the fix in the SMR Jul-2026 Release 1 monthly security update. Administrators should push the update through carrier channels or MDM platforms. Details are available in the Samsung Mobile Security Update for July 2026.
Workarounds
- Limit sideloading and enforce Google Play Protect or equivalent application vetting on unpatched devices
- Enforce MDM policies that restrict which applications can be installed on corporate-managed Samsung devices
- Isolate unpatched devices from sensitive corporate resources until the July 2026 update is applied
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
