CVE-2026-21030: MediaTek Audio HAL Access Control Bypass on Samsung Android

Technical summary

CVE-2026-21030 represents an access control failure in the MediaTek Audio HAL, a low-level system component responsible for interfacing between Android's audio framework and hardware drivers. The vulnerability allows a local, low-privileged process or application to invoke privileged audio HAL functions without proper authorization checks. The issue affects devices running Samsung Android implementations that use vulnerable versions of this MediaTek component. Remediation is available through the SMR (Security Maintenance Release) June 2026 Release 1 and later patches that implement proper permission validation in the audio HAL.

Business impact

For organizations deploying Samsung Android devices—particularly in enterprise environments—this vulnerability poses a direct threat to device integrity and confidentiality. A compromised or malicious app could manipulate audio settings, record communications without proper authorization, or leverage the privileged access as a stepping stone to compromise other device functions. In sensitive use cases (medical, financial, or classified environments), this represents a material security gap that must be addressed urgently. The vulnerability is not yet widely exploited in the wild, but the ease of exploitation once device access is gained makes rapid patching a business imperative.

Affected systems

This vulnerability affects Samsung Android devices utilizing the vulnerable MediaTek Audio HAL. The source data indicates a broad range of Samsung Android implementations are impacted. Organizations should cross-reference their device inventory against the specific Samsung Android versions and device models confirmed by Samsung's security bulletin to determine precise exposure. Devices running patched versions from the SMR June 2026 Release 1 or later are not vulnerable.

Exploitability

The vulnerability carries a CVSS v3.1 score of 7.8 (HIGH) with a local attack vector, low attack complexity, and low privilege requirements—meaning an attacker needs initial access to the device but no special conditions to trigger the flaw. The lack of user interaction (UI:N) is significant; exploitation does not require user awareness or approval. However, the local-only attack vector means the attacker must first gain some foothold on the device, whether through a previous vulnerability, physical access, or installation of a malicious app. The vulnerability is not yet listed on CISA's Known Exploited Vulnerabilities (KEV) catalog, suggesting limited active exploitation at publication time, though this should not delay patching.

Remediation

MediaTek and Samsung have addressed this vulnerability in the SMR June 2026 Release 1 and subsequent patches. Device owners and administrators should prioritize applying available security updates. For enterprises, this should trigger immediate device management system updates to distribute patches to affected Samsung Android devices. Consult Samsung's official security advisory and your device management platform (MDM/EMM) to verify patch availability for your specific device models. Interim mitigations include restricting app permissions and monitoring for suspicious audio-related activity, though patching is the only complete fix.

Patch guidance

Apply security updates from the SMR June 2026 Release 1 or later as made available by Samsung for your specific device model and Android version. Check your device's Settings > System > System Update or your enterprise management console for available patches. Verify patch status against Samsung's official security bulletin to confirm your device is running a patched firmware version. Prioritize deployment in high-risk environments (enterprise, healthcare, finance) ahead of general rollout. Test patches in a controlled environment before broad deployment to ensure compatibility with organizational applications.

Detection guidance

Monitor for signs of unauthorized audio HAL function invocation: unusual logcat entries from audio-related processes, unexpected changes to audio permissions for apps, or processes attempting to access audio system resources with insufficient privileges. Implement application-level monitoring on high-risk devices to track which apps request audio permissions and actively use audio APIs. Security Information and Event Management (SIEM) systems with Android app telemetry integration can flag suspicious audio subsystem activity. Most importantly, verify patch compliance across your device fleet using your MDM solution before the vulnerability is actively weaponized in the wild.

Why prioritize this

This vulnerability demands swift action due to its HIGH CVSS score, local but low-barrier exploitation path, and the broad attack surface of consumer-facing Samsung devices in enterprise environments. The fact that it does not yet appear on the KEV catalog suggests a window of opportunity before widespread exploitation—patch now rather than respond to breaches. The ability to manipulate audio functions without user awareness creates both privacy and integrity risks, particularly in organizations handling sensitive communications.

Risk score, explained

The CVSS v3.1 score of 7.8 reflects high impact (CIA:H/H/H) on a local scope. The local attack vector (AV:L) prevents remote exploitation, but the low privilege requirement (PR:L) and low attack complexity (AC:L) mean any local attacker—whether via a compromised app, previous vulnerability, or physical access—can trigger it. The lack of user interaction means no social engineering is needed. This scoring appropriately captures the severity of an access control bypass that grants full compromise of audio subsystem functionality to a low-privileged context.

Frequently asked questions