CVE-2026-21058 Overview
CVE-2026-21058 is an improper input validation vulnerability in the Samsung Contacts application on Samsung mobile devices. The flaw allows a local attacker to delete arbitrary files with the privilege of the Samsung Contacts application. Samsung addressed the issue in the SMR Aug-2026 Release 1 security maintenance release. The vulnerability is tracked under CWE-20: Improper Input Validation.
Critical Impact
Local attackers can delete files accessible to the Samsung Contacts application, compromising integrity of contact data and related resources on affected Samsung devices.
Affected Products
- Samsung Contacts application on Samsung mobile devices
- Samsung mobile devices prior to SMR Aug-2026 Release 1
- Samsung Mobile Security Maintenance Release (SMR) builds before August 2026
Discovery Timeline
- 2026-08-10 - CVE-2026-21058 published to NVD
- 2026-08-10 - Last updated in NVD database
Technical Details for CVE-2026-21058
Vulnerability Analysis
The Samsung Contacts application fails to properly validate input passed to a file handling routine. A local attacker on the device can supply crafted input that causes the application to delete files it has permission to access. Because Samsung Contacts holds elevated privileges over user contact data and related storage, the attacker can affect resources that would otherwise be inaccessible to a low-privilege process.
The vulnerability requires local access to the device and does not require user interaction. Exploitation impacts integrity only; there is no direct confidentiality or availability impact against the wider system, though deleted data may be unrecoverable.
Root Cause
The root cause is missing or insufficient validation of input consumed by the Samsung Contacts application before it performs a file deletion operation. Classified as [CWE-20: Improper Input Validation], the flaw enables a caller to influence the file path or identifier used by the deletion routine.
Attack Vector
An attacker with local access, such as a malicious application installed on the device, invokes the vulnerable code path in Samsung Contacts. The malicious input reaches the file operation and causes the deletion of files under the privilege boundary of Samsung Contacts. See the Samsung Security Update August 2026 for advisory details.
No public proof-of-concept has been published for this issue, and it is not listed in the CISA Known Exploited Vulnerabilities catalog.
Detection Methods for CVE-2026-21058
Indicators of Compromise
- Unexpected deletion of contact database files or related Samsung Contacts storage artifacts on the device.
- Installed third-party applications making unusual inter-process calls to the Samsung Contacts package.
- Samsung Contacts crash logs or file-not-found errors correlated with recent app installs.
Detection Strategies
- Monitor mobile device management (MDM) telemetry for Samsung devices running SMR builds older than August 2026 Release 1.
- Review installed application inventories for untrusted apps requesting or interacting with Contacts intents.
- Audit Android logcat data, when accessible, for anomalous activity referencing the com.samsung.android.app.contacts package.
Monitoring Recommendations
- Track Samsung security patch level (SPL) across the mobile fleet and flag devices below the August 2026 SMR baseline.
- Alert on unauthorized side-loaded applications on managed Samsung devices.
- Correlate contacts data loss reports from users with device patch status for triage.
How to Mitigate CVE-2026-21058
Immediate Actions Required
- Apply Samsung SMR Aug-2026 Release 1 or later to all affected Samsung mobile devices.
- Enforce minimum security patch level policies through MDM to block non-compliant devices from sensitive resources.
- Restrict installation of untrusted third-party applications on managed devices.
Patch Information
Samsung released the fix in the SMR Aug-2026 Release 1 security maintenance release. Refer to the Samsung Security Update August 2026 advisory for device-specific patch availability and rollout timing.
Workarounds
- Limit local access to devices and prohibit installation of applications from unknown sources until patched.
- Use MDM policies to enforce Google Play Protect and block sideloading on affected Samsung devices.
- Back up contacts data to a trusted cloud account to allow recovery if files are deleted before patching.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
