CVE-2026-21102: DualDAR Use After Free Vulnerability

CVE-2026-21102 Overview

CVE-2026-21102 is a use-after-free vulnerability in Samsung's DualDAR (Dual Data-at-Rest) encryption component. The flaw affects Samsung mobile devices prior to the SMR (Security Maintenance Release) Sep-2026 Release 1. Local attackers with high privileges can exploit the freed memory reference to execute arbitrary code with root privilege. Samsung addressed the issue in its September 2026 mobile security update.

Critical Impact
Successful exploitation grants root-level code execution on affected Samsung devices, compromising the confidentiality, integrity, and availability of the entire mobile platform.

Affected Products

Samsung mobile devices with DualDAR encryption support
Firmware releases prior to SMR Sep-2026 Release 1
Samsung Knox-enabled Android builds shipping the vulnerable DualDAR component

Discovery Timeline

2026-09-09 - CVE-2026-21102 published to NVD
2026-09-09 - Samsung releases SMR Sep-2026 Release 1 security patch
2026-09-09 - Last updated in NVD database

Technical Details for CVE-2026-21102

Vulnerability Analysis

DualDAR provides a second layer of file-based encryption on Samsung Knox devices, protecting workspace data even when the device is unlocked. The vulnerability is a use-after-free condition, meaning the component continues to reference a memory object after it has been freed. An attacker who triggers the dangling reference can influence the freed allocation to gain control over the execution flow within a privileged process. Because DualDAR runs with elevated privileges tied to device encryption services, successful exploitation yields root-level code execution.

Root Cause

The root cause is improper lifetime management of a heap-allocated object inside the DualDAR subsystem. A code path releases the object while another path retains and later dereferences the stale pointer. Samsung has not published the specific function or structure involved in the public advisory.

Attack Vector

Exploitation requires local access with high privileges on the target device. An attacker with a foothold in a privileged process or component can invoke the vulnerable DualDAR interface, reclaim the freed allocation with attacker-controlled data, and pivot from high-privilege to root-level execution. User interaction is not required. Refer to the Samsung Mobile Security Update for vendor technical details.

// No verified public proof-of-concept is available for CVE-2026-21102.
// See the Samsung Mobile Security Update advisory for vendor details.

Detection Methods for CVE-2026-21102

Indicators of Compromise

Unexpected crashes, tombstones, or kernel logs referencing the DualDAR component or its associated services
New or unauthorized processes running with root privilege following interaction with encrypted workspace storage
Modification of Knox or DualDAR runtime configuration outside of managed update channels

Detection Strategies

Track SMR patch level on managed Samsung devices and flag builds older than SMR Sep-2026 Release 1
Correlate privileged process crashes with subsequent privilege escalation events on the same device
Review mobile threat defense telemetry for anomalous access patterns to DualDAR-protected containers

Monitoring Recommendations

Ingest Android and Samsung Knox device logs into a centralized data lake for longitudinal analysis
Alert on repeated segmentation faults or aborts in encryption service processes
Monitor enterprise mobility management (EMM) inventory for devices that fall behind the September 2026 patch baseline

How to Mitigate CVE-2026-21102

Immediate Actions Required

Apply Samsung SMR Sep-2026 Release 1 or later to all affected devices as soon as the OTA update is available
Prioritize patching devices used by administrators and users with access to sensitive Knox workspaces
Audit installed applications with elevated privileges and remove any that are unnecessary or untrusted

Patch Information

Samsung addressed CVE-2026-21102 in the SMR Sep-2026 Release 1 security maintenance release. Deploy the update through carrier OTA, Samsung Knox Mobile Enrollment, or the EMM platform in use. See the Samsung Mobile Security Update for the official bulletin and firmware version mapping.

Workarounds

No vendor-supplied workaround exists; patching is the only supported remediation
Restrict installation of third-party applications and sideloading on devices awaiting the update
Enforce EMM compliance policies that block devices below the September 2026 patch level from accessing corporate resources

bash

# Verify the security patch level on a connected Samsung device
adb shell getprop ro.build.version.security_patch
# Expected value: 2026-09-01 or later after applying SMR Sep-2026 Release 1