CVE-2026-21006: 
NixOS vulnerability analysis and mitigation

CVE-2026-21006 is an improper access control vulnerability in Samsung DeX that allows physical attackers to access hidden notification contents on affected devices. It affects Samsung Android 15.0 across all monthly security releases prior to SMR Apr-2026 Release 1 (from SMR Jan-2025-R1 through SMR Mar-2026-R1). The vulnerability was published on April 13, 2026, by Samsung Mobile. It carries a CVSS v3.1 base score of 2.4 (Low) and a CVSS v4.0 base score of 4.7 (Medium) (Samsung Advisory, GitHub Advisory).

The vulnerability is classified as improper access control (CWE-284), where Samsung DeX fails to properly enforce restrictions on notification content visibility. An attacker with physical access to the device can interact with the DeX interface to bypass the access controls that are intended to hide sensitive notification contents. No authentication or elevated privileges are required, and no user interaction is needed beyond the attacker's own physical manipulation of the device. No detailed technical write-ups or proof-of-concept code have been publicly disclosed (Samsung Advisory, GitHub Advisory).

Successful exploitation allows a physical attacker to view notification contents that the device owner has configured to be hidden or restricted — such as private messages, alerts, or other sensitive notification data. The impact is limited to confidentiality of notification content on the vulnerable system; there is no integrity or availability impact on the directly vulnerable system. However, the CVSS v4.0 scoring notes high subsequent system confidentiality, integrity, and availability impact, reflecting potential downstream risk if exposed notification data enables further unauthorized access (GitHub Advisory, Samsung Advisory).

There is no public proof-of-concept exploit and no evidence of active in-the-wild exploitation as of the time of publication. The vulnerability requires physical access to the device, significantly limiting the attacker pool. The EPSS score is approximately 0.021% (7th percentile), indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (GitHub Advisory, Samsung Advisory).

Samsung has released a fix in the SMR Apr-2026 Release 1 security update for Samsung Android 15.0. Users and administrators should apply this update or any later monthly security release to remediate the vulnerability. As an interim measure for devices that cannot be immediately patched, organizations should implement physical security controls to restrict unauthorized access to devices and consider adjusting notification visibility settings to minimize exposure of sensitive content (Samsung Advisory, GitHub Advisory).