CVE-2026-21064: Weaver Privilege Escalation Vulnerability

CVE-2026-21064 Overview

CVE-2026-21064 is an improper access control vulnerability [CWE-284] in the Weaver component of Samsung Mobile devices. The flaw affects builds prior to the Samsung Maintenance Release (SMR) Aug-2026 Release 1. Local attackers can abuse the missing access restrictions to render the device inoperable.

Exploitation requires local access to the affected device but does not require privileges or user interaction. The vulnerability impacts integrity and availability while leaving confidentiality unaffected. Samsung addressed the issue in its August 2026 mobile security maintenance release.

Critical Impact
A local attacker can trigger device inoperability on affected Samsung mobile devices running Weaver builds prior to SMR Aug-2026 Release 1, disrupting availability of the device.

Affected Products

Samsung Mobile devices running Weaver prior to SMR Aug-2026 Release 1
Samsung mobile firmware builds released before the August 2026 SMR
Devices that have not applied the Samsung Mobile Security Update for August 2026

Discovery Timeline

2026-08-10 - CVE-2026-21064 published to the National Vulnerability Database (NVD)
2026-08-10 - Last updated in NVD database

Technical Details for CVE-2026-21064

Vulnerability Analysis

The vulnerability resides in Weaver, a component present in the Samsung Mobile software stack. Weaver did not enforce sufficient access control on privileged operations exposed to local callers. A local process without elevated privileges can invoke functionality that alters state required for normal device operation.

Because the check is missing rather than merely weak, the attacker does not need to bypass a validation routine. Invoking the exposed interface is enough to cause the device to become inoperable. The result is a persistent denial-of-service condition impacting device availability.

Root Cause

The root cause is improper access control [CWE-284] within the Weaver component. Weaver exposes an interface that fails to verify caller identity or permissions before executing state-changing operations. This design flaw allows any local application to reach code paths that should be restricted to trusted callers.

Attack Vector

The attack vector is local. An adversary must first deliver code to the device, typically through a malicious or trojanized Android application, and then invoke the vulnerable Weaver interface at runtime. No user interaction and no prior authentication are required to trigger the condition once the malicious code is executing on the device.

No verified public exploit code is available at the time of publication. See the Samsung Mobile Security Update for advisory-level technical details.

Detection Methods for CVE-2026-21064

Indicators of Compromise

Unexpected device reboots, boot loops, or bricked-state behavior on Samsung mobile devices that have not applied the August 2026 SMR
Installation of untrusted third-party APKs shortly before device inoperability
Application logs showing invocation of Weaver interfaces by non-system UIDs

Detection Strategies

Inventory Samsung mobile devices and identify those running firmware builds prior to SMR Aug-2026 Release 1
Monitor enterprise mobility management (EMM) or mobile device management (MDM) telemetry for devices that fail to check in after abnormal shutdown events
Review sideloaded application activity on managed devices, particularly apps requesting broad system-level interactions

Monitoring Recommendations

Track Samsung SMR patch level compliance across the mobile fleet through MDM reporting
Alert on repeated abnormal device unresponsiveness reported by end users or endpoint agents
Correlate crash and reboot telemetry with recent application installation events to identify potential exploitation attempts

How to Mitigate CVE-2026-21064

Immediate Actions Required

Apply the Samsung SMR Aug-2026 Release 1 update to all affected Samsung mobile devices as soon as it becomes available for each model
Enforce patch compliance through MDM policies and block non-compliant devices from accessing corporate resources
Restrict installation of applications from unknown sources on managed devices

Patch Information

Samsung addressed CVE-2026-21064 in the SMR Aug-2026 Release 1 security maintenance release. Refer to the Samsung Mobile Security Update advisory for per-model patch availability. Device firmware updates are distributed by carriers and Samsung according to model and region.

Workarounds

Prohibit sideloading of untrusted APKs and enforce Google Play Protect on managed devices
Use MDM configuration profiles to restrict permissions available to non-system applications
Isolate unpatched devices from sensitive corporate workloads until the SMR Aug-2026 Release 1 update is applied

bash

# Verify Samsung security patch level on an Android device via adb
adb shell getprop ro.build.version.security_patch

# Expected value: 2026-08-01 or later once SMR Aug-2026 Release 1 is applied