CVE-2026-20978 is an improper authorization vulnerability (CWE-269) found in Samsung Mobile Devices' KnoxGuardManager component prior to the SMR Feb-2026 Release 1 update. KnoxGuardManager is part of Samsung's Knox security framework, responsible for managing device security policies and persistence configurations. The vulnerability allows a local attacker with limited privileges (partial rights) to bypass the persistence configuration controls of the application. This means an attacker could potentially alter or disable persistence mechanisms that ensure security policies or protections remain active after reboots or other system events. The CVSS 4.0 score of 5.8 reflects a medium severity, with attack vector being local (AV:L), low attack complexity (AC:L), partial attack type (AT:P), and requiring low privileges (PR:L). No user interaction is needed (UI:N), and the impact is primarily on integrity (VI:H) with low impact on availability (VA:L) and no impact on confidentiality or system components. No known exploits have been reported in the wild, and Samsung has reserved the CVE and published the vulnerability details. The vulnerability affects all Samsung Mobile Devices running KnoxGuardManager versions prior to the February 2026 security update, though exact affected versions are unspecified. The flaw could be leveraged by an attacker who already has some local access to the device, such as through a compromised app or user account, to undermine security persistence, potentially facilitating further attacks or persistence of malicious code.

For European organizations, this vulnerability poses a risk primarily to the integrity of Samsung mobile devices used within corporate environments. Since KnoxGuardManager is integral to enforcing security policies and persistence, bypassing its controls could allow attackers to maintain unauthorized access or disable security features persistently. This could lead to prolonged device compromise, data tampering, or unauthorized configuration changes. While confidentiality and availability impacts are low, the integrity compromise can undermine trust in device security, especially in regulated sectors such as finance, healthcare, and government. Organizations relying heavily on Samsung devices for secure mobile communications and data handling may face increased risk of targeted local attacks, particularly if endpoint protection or device access controls are weak. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits post-disclosure.

1. Apply the Samsung SMR (Security Maintenance Release) February 2026 update as soon as it becomes available to ensure the KnoxGuardManager vulnerability is patched. 2. Enforce strict local access controls on Samsung mobile devices, limiting user privileges to the minimum necessary and preventing unauthorized local access. 3. Employ mobile device management (MDM) solutions to monitor and enforce security policies, detect unauthorized changes to persistence configurations, and respond to suspicious activity. 4. Regularly audit device configurations and Knox security settings to detect anomalies or unauthorized modifications. 5. Educate users about the risks of installing untrusted applications or granting excessive permissions that could facilitate local privilege escalation. 6. Consider additional endpoint protection tools that can detect and block attempts to tamper with security persistence mechanisms. 7. Maintain an incident response plan that includes mobile device compromise scenarios to quickly contain and remediate any exploitation attempts.