CVE-2026-21000 Overview
CVE-2026-21000 is an improper access control vulnerability in the Samsung Galaxy Store application affecting versions prior to 4.6.03.8. The flaw allows a local attacker to create files using the Galaxy Store's elevated privileges. Samsung addressed the issue in its March 2026 mobile security update.
The vulnerability is tracked under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory). Exploitation requires local access to a Samsung device but no user interaction or prior authentication. Successful exploitation can lead to integrity compromise of files within the Galaxy Store's security context.
Critical Impact
A local attacker can create arbitrary files with Galaxy Store privileges, enabling persistence, configuration tampering, or staging for further privilege escalation on affected Samsung devices.
Affected Products
- Samsung Galaxy Store versions prior to 4.6.03.8
- Samsung mobile devices with Galaxy Store pre-installed
- Android-based Galaxy devices running vulnerable Galaxy Store builds
Discovery Timeline
- 2026-03-16 - CVE-2026-21000 published to NVD
- 2026-03 - Samsung releases March 2026 Mobile Security Update addressing the issue
- 2026-04-07 - Last updated in NVD database
Technical Details for CVE-2026-21000
Vulnerability Analysis
The vulnerability resides in the Samsung Galaxy Store application, which runs with elevated privileges on Samsung Android devices. Galaxy Store handles application installation, updates, and content delivery, requiring access to protected storage locations and system directories.
Improper access control checks in the affected component allow a local attacker to invoke file creation operations through the Galaxy Store process. Because the operations execute under the Galaxy Store's identity, the resulting files inherit its privilege level rather than the calling application's restricted permissions.
The CWE-22 classification indicates that pathname validation is insufficient. An attacker can supply crafted file paths that escape the intended directory boundaries, enabling file writes in locations the calling application should not reach.
Root Cause
The root cause is missing or insufficient access control validation on an exported interface within Galaxy Store prior to 4.6.03.8. The application accepts file creation requests from local callers without verifying whether the caller is authorized to write to the target path. The combination of permissive input handling and elevated process privileges produces the privilege boundary violation.
Attack Vector
Exploitation requires a malicious or compromised local application installed on the Samsung device. The attacking application interacts with the vulnerable Galaxy Store interface, supplying a target file path and content. Galaxy Store then performs the file creation operation under its own privileges, producing a file the attacker could not have created directly.
No user interaction is required during exploitation. The attack does not require network access, and the EPSS score of 0.025% reflects the local-only attack surface and the requirement for an existing foothold on the device.
Readers should consult the Samsung Mobile Security Update for vendor-specific technical details, as Samsung has not published a public proof-of-concept.
Detection Methods for CVE-2026-21000
Indicators of Compromise
- Unexpected files appearing in directories owned by the Galaxy Store process or its data sandbox
- Galaxy Store process activity correlated with file writes outside its normal update and cache paths
- Installation of untrusted third-party APKs shortly before suspicious file creation events
- Galaxy Store version strings below 4.6.03.8 reported by mobile device management (MDM) inventory
Detection Strategies
- Inventory Samsung devices through MDM or unified endpoint management to identify Galaxy Store builds prior to 4.6.03.8
- Monitor mobile threat defense telemetry for inter-process communication patterns targeting Galaxy Store exported components
- Review application install logs for sideloaded apps that request unusual interactions with Samsung system applications
Monitoring Recommendations
- Enroll Samsung devices in mobile threat defense tooling that flags vulnerable application versions
- Correlate Galaxy Store update events with the March 2026 patch baseline across the device fleet
- Track newly installed applications on managed Samsung devices and flag those requesting access to Galaxy Store interfaces
How to Mitigate CVE-2026-21000
Immediate Actions Required
- Update Galaxy Store to version 4.6.03.8 or later on all Samsung devices through the in-app update mechanism
- Verify deployment of the March 2026 Samsung Mobile Security Update across the managed device fleet
- Restrict installation of applications from untrusted sources by enforcing MDM policy on Samsung devices
- Audit installed applications on Samsung devices and remove any unrecognized or sideloaded packages
Patch Information
Samsung released the fix in Galaxy Store version 4.6.03.8 as part of the March 2026 mobile security update. Patch details and the official advisory are available in the Samsung Mobile Security Update. Galaxy Store typically updates automatically when devices connect to Wi-Fi, but administrators should confirm the deployed version through MDM reporting.
Workarounds
- Disable sideloading and restrict installation sources to vetted enterprise catalogs until devices receive the patched Galaxy Store build
- Apply MDM compliance rules that block or quarantine devices running Galaxy Store versions earlier than 4.6.03.8
- Educate users to avoid installing applications from unverified sources that could exploit the local attack vector
# Verify Galaxy Store version via ADB on a managed device
adb shell dumpsys package com.sec.android.app.samsungapps | grep versionName
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
