CVE-2026-21099 Overview
CVE-2026-21099 is an improper access control vulnerability [CWE-280] in the Samsung SettingsProvider component. The flaw allows a local attacker on an affected Samsung device to read sensitive information that should be restricted. Samsung addressed the issue in the Security Maintenance Release (SMR) for September 2026, Release 1. The vulnerability requires local access and no user interaction, but does not permit modification of data or impact device availability.
Critical Impact
A local application or attacker on an affected Samsung device can read sensitive information exposed by SettingsProvider without user interaction, breaching confidentiality boundaries between apps.
Affected Products
- Samsung Mobile devices running firmware prior to SMR Sep-2026 Release 1
- Samsung SettingsProvider system component
- Samsung Android-based mobile platform
Discovery Timeline
- 2026-09-09 - CVE-2026-21099 published to the National Vulnerability Database
- 2026-09-10 - Entry last updated in the NVD database
- September 2026 - Samsung releases SMR Sep-2026 Release 1 addressing the issue
Technical Details for CVE-2026-21099
Vulnerability Analysis
The vulnerability resides in Samsung's SettingsProvider, a system content provider that stores device configuration and user preference data on Android. Improper access control [CWE-280] permits a locally installed application or on-device attacker to query data that should be restricted to privileged callers.
Exploitation does not require authentication or user interaction, but the attacker must already have code execution or an installed application on the device. The impact is limited to confidentiality; integrity and availability are not affected. Because SettingsProvider may store telephony, account, or configuration data, disclosed values can support follow-on attacks such as device fingerprinting or targeted phishing.
Root Cause
The issue is a failure to properly honor or enforce permission attributes on protected content provider entries within SettingsProvider. When access control checks are incomplete, callers that should be denied by the manifest-declared permissions can still retrieve protected values. Samsung's advisory identifies the fix as part of the SMR Sep-2026 Release 1 monthly maintenance release.
Attack Vector
The attack vector is local. A malicious or over-privileged Android application installed on an affected Samsung device queries SettingsProvider through standard content resolver APIs. Because the access control check is insufficient, the query returns data the caller should not be allowed to read. No user interaction is required, and no elevated privileges are needed to trigger the flaw.
No public proof-of-concept exploit is available at time of publication, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Detailed technical mechanics have not been published by the vendor. Refer to the Samsung Mobile Security Update for advisory details.
Detection Methods for CVE-2026-21099
Indicators of Compromise
- Installed applications that query SettingsProvider URIs outside of their declared functional scope.
- Unexpected content resolver calls from third-party packages targeting protected settings keys.
- Devices reporting a build fingerprint older than the SMR Sep-2026 Release 1 patch level.
Detection Strategies
- Enroll Samsung devices in mobile device management (MDM) and alert when the security patch level is earlier than September 2026.
- Review installed applications on managed devices for excessive use of content provider queries against system providers.
- Correlate application inventory with vendor advisories to identify apps that request or abuse access to device configuration data.
Monitoring Recommendations
- Track Samsung device patch level attestation through MDM or Android Enterprise reporting.
- Monitor for sideloaded applications on corporate-managed Samsung devices, which increases the local-attacker risk.
- Audit mobile threat defense telemetry for applications flagged as accessing sensitive system data.
How to Mitigate CVE-2026-21099
Immediate Actions Required
- Apply the Samsung SMR Sep-2026 Release 1 firmware update to all affected Samsung mobile devices.
- Verify the Android security patch level on managed devices is dated September 2026 or later.
- Restrict installation of untrusted or sideloaded applications on corporate devices through MDM policy.
Patch Information
Samsung addressed CVE-2026-21099 in the Security Maintenance Release for September 2026, Release 1. Details are published in the Samsung Mobile Security Update bulletin. Users should install the update through Settings → Software update → Download and install once the carrier or vendor makes it available for their model.
Workarounds
- Limit installation of third-party applications from outside Google Play or Galaxy Store until the patch is applied.
- Enforce work profile separation so business data remains isolated from potentially malicious personal-profile apps.
- Use MDM to block or uninstall applications flagged for abusive content provider access on unpatched devices.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.