CVE-2026-21101: DualDAR Driver Privilege Escalation Flaw

CVE-2026-21101 Overview

CVE-2026-21101 is a high-severity improper input validation vulnerability in the Samsung DualDAR (Dual Data-at-Rest) encryption driver. The flaw exists in versions prior to the Samsung Mobile Release (SMR) September 2026 Release 1. A local attacker with elevated privileges can supply crafted input to the driver and execute arbitrary code with root privileges. Samsung addressed the issue in the September 2026 security maintenance release.

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

Affected Products

Samsung DualDAR driver versions prior to SMR Sep-2026 Release 1
Samsung mobile devices shipping with the DualDAR encryption framework
Enterprise-managed Samsung Knox deployments relying on DualDAR for data-at-rest protection

Discovery Timeline

2026-09-09 - CVE-2026-21101 published to the National Vulnerability Database (NVD)
2026-09-09 - Samsung publishes the September 2026 Security Maintenance Release addressing the issue
2026-09-09 - Last updated in NVD database

Technical Details for CVE-2026-21101

Vulnerability Analysis

The DualDAR driver implements two-layer encryption for data at rest on Samsung mobile devices. The vulnerability stems from improper input validation of data passed into the driver from user space. A local attacker who already holds elevated privileges can pass crafted parameters to the driver interface and trigger unsafe processing inside the kernel context.

Because the driver runs with kernel privileges, mishandled input can lead to arbitrary code execution as root. This effectively bypasses the Android security model and Knox container boundaries that DualDAR is designed to enforce. The vulnerability is classified as Improper Input Validation, which aligns with [CWE-20].

Root Cause

The root cause is missing or insufficient validation of untrusted parameters received by the DualDAR driver through its kernel interface. The driver accepts input without enforcing the expected bounds, types, or state constraints. This allows a privileged local process to influence kernel execution paths that were not designed to accept attacker-controlled values.

Attack Vector

The attack vector is local and requires high privileges on the target device. An attacker must first obtain elevated access, for example through a compromised system service, a chained user-space exploit, or a malicious application granted system-level permissions. Once positioned, the attacker interacts with the DualDAR driver interface to deliver the malformed input. No user interaction is required. Because the flaw resides in a kernel driver, successful exploitation escalates from privileged user context to full root execution.

No public proof-of-concept exploit is currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. See the Samsung Security Update September 2026 advisory for vendor-specific technical details.

Detection Methods for CVE-2026-21101

Indicators of Compromise

Unexpected kernel panics, oops messages, or crashes referencing the DualDAR driver in device logs
Unauthorized processes issuing ioctl or system calls against the DualDAR device node
New root-owned processes spawned by services that historically operate with lower privileges
Modifications to DualDAR-protected containers or encryption keys outside of Knox management workflows

Detection Strategies

Collect and centralize Android and Knox device logs, then hunt for anomalous interactions with the DualDAR kernel interface
Correlate privilege escalation events on managed devices with subsequent access to encrypted containers
Deploy mobile threat defense agents that monitor for kernel exploitation behaviors and driver abuse
Baseline expected callers of the DualDAR interface and alert on deviations from that baseline

Monitoring Recommendations

Ingest Samsung Knox audit events and Android system logs into a centralized analytics platform for retrospective hunting
Track patch level (ro.build.version.security_patch) across the fleet and flag devices below September 2026
Monitor for applications requesting or acquiring system-level privileges outside of approved enterprise workflows
Alert on rooted device indicators or attestation failures reported by Knox Attestation

How to Mitigate CVE-2026-21101

Immediate Actions Required

Apply the SMR Sep-2026 Release 1 update to all affected Samsung devices as soon as it becomes available for the specific device model
Enforce mobile device management (MDM) policies that block enrollment or access from devices below the September 2026 patch level
Audit installed applications for those holding system or privileged permissions and remove any that are not required
Validate device integrity using Samsung Knox Attestation before granting access to sensitive enterprise resources

Patch Information

Samsung addressed CVE-2026-21101 in the September 2026 Security Maintenance Release (SMR Sep-2026 Release 1). Device owners and enterprise administrators should push the update through carrier channels or MDM as soon as the vendor publishes it for the relevant device model. Refer to the Samsung Security Update September 2026 advisory for the current list of models receiving the patch.

Workarounds

Restrict installation of applications from untrusted sources and enforce Google Play Protect or equivalent controls
Require Knox attestation and current patch level as conditional access requirements for corporate resources
Limit assignment of system-level privileges to only vetted enterprise applications
Isolate high-risk devices from sensitive networks and data until the September 2026 patch is applied

bash

# Verify current Android security patch level on a managed device
adb shell getprop ro.build.version.security_patch

# Expected value on patched devices: 2026-09-01 or later