CVE-2026-21059: Samsung Contacts Privilege Escalation Flaw

CVE-2026-21059 Overview

CVE-2026-21059 is a medium-severity vulnerability in Samsung Contacts caused by improper export of Android application components [CWE-926]. The flaw affects Samsung Contacts versions prior to the SMR (Security Maintenance Release) Aug-2026 Release 1. A local attacker with an application installed on the device can abuse an exported component to delete files with the privileges of the Samsung Contacts application. Exploitation requires no user interaction and no privileges beyond running a local app. Samsung addressed the issue in the August 2026 security maintenance release.

Critical Impact
A local malicious application can delete files accessible to Samsung Contacts without user interaction, impacting integrity of contact data and related storage on affected Samsung Android devices.

Affected Products

Samsung Contacts application on Android
Samsung Contacts versions prior to SMR Aug-2026 Release 1
Samsung Android devices running vulnerable Samsung Contacts builds

Discovery Timeline

2026-08-10 - CVE-2026-21059 published to the National Vulnerability Database
2026-08-10 - Last updated in NVD database
August 2026 - Samsung releases SMR Aug-2026 Release 1 addressing the issue

Technical Details for CVE-2026-21059

Vulnerability Analysis

The vulnerability is classified under CWE-926: Improper Export of Android Application Components. Samsung Contacts exposes one or more Android components (activities, services, receivers, or providers) with an insufficiently restricted export configuration. A co-resident application can send crafted Intents to the exposed component. The receiving code performs a file deletion operation using paths influenced by the caller. Because the deletion runs under the Samsung Contacts process identity, the attacker inherits that application's file access rights on the device.

The attack vector is local. The attacker must run code on the device, typically through a separately installed application. No permissions and no user interaction are required to reach the vulnerable component. The scope is limited to integrity impact; the flaw does not expose confidential data or affect availability of the wider system.

Root Cause

The root cause is an Android component declared or protected in a way that permits arbitrary applications to invoke functionality that should be restricted to the Samsung Contacts package or to callers holding a matching signature-level permission. The invoked code path performs a file removal without adequately validating the caller's identity or sanitizing the target path.

Attack Vector

A local application sends an Intent to the exported Samsung Contacts component. The Intent supplies parameters that direct the vulnerable handler to remove a file within the storage areas accessible to Samsung Contacts. The operation completes under the privileges of Samsung Contacts, resulting in unauthorized file deletion. See the Samsung Mobile Security Update for vendor-published details.

Exploitation prerequisites (prose description):
1. Attacker installs an app on a vulnerable Samsung device.
2. The app targets the exported Samsung Contacts component.
3. The Intent triggers a file deletion under Samsung Contacts' UID.
No verified proof-of-concept code is publicly available.

Detection Methods for CVE-2026-21059

Indicators of Compromise

Unexpected disappearance of files or records managed by the Samsung Contacts application, such as contact databases or cached attachments.
Installed third-party applications issuing Intents targeting Samsung Contacts package components without a legitimate integration purpose.
Anomalous startActivity, startService, or sendBroadcast events in Android application logs directed at Samsung Contacts.

Detection Strategies

Enumerate installed Samsung Contacts versions across the mobile fleet using Mobile Device Management (MDM) inventory and flag builds prior to SMR Aug-2026 Release 1.
Review Android manifest exports and permission declarations for Samsung Contacts on managed devices using MDM attestation data.
Correlate mobile threat defense telemetry for applications that issue Intents to com.samsung.android.app.contacts or related packages.

Monitoring Recommendations

Track Samsung security bulletin adoption across managed Android endpoints and require SMR Aug-2026 or later.
Monitor for sideloaded or newly installed applications on corporate Android devices and evaluate their Intent activity.
Alert on user reports of missing contact records or Samsung Contacts data loss that could indicate exploitation.

How to Mitigate CVE-2026-21059

Immediate Actions Required

Apply the Samsung SMR Aug-2026 Release 1 security maintenance release on all affected Samsung Android devices.
Enforce the updated Samsung Contacts build through MDM policy and block noncompliant devices from sensitive corporate resources.
Audit installed third-party applications and remove untrusted or unnecessary apps that could stage local exploitation.

Patch Information

Samsung released the fix in SMR Aug-2026 Release 1. Details are published in the Samsung Mobile Security Update for August 2026. Devices must receive the vendor and carrier security patch that corresponds to this SMR level. Verify the patch level under Settings > About phone > Software information > Android security update.

Workarounds

Restrict application installation on managed Samsung devices to vetted sources using MDM controls until the patch is applied.
Disable or uninstall the Samsung Contacts application on devices where it is not required and where an alternative contacts application is available.
Educate users to avoid installing untrusted applications that could exercise the vulnerable exported component.

bash

# Verify Android security patch level on a Samsung device via ADB
adb shell getprop ro.build.version.security_patch
# Expected: a date at or after the August 2026 Samsung security maintenance release