CVE-2026-20451 Overview
CVE-2026-20451 is an out-of-bounds write vulnerability caused by type confusion [CWE-843] in the slbc component used across a wide range of MediaTek system-on-chip (SoC) firmware. The flaw allows a local attacker who already holds System privilege to escalate further by triggering memory corruption inside the affected driver. Exploitation requires no user interaction. MediaTek tracks the fix as Patch ID ALPS10828685 and Issue ID MSV-6504, published in the MediaTek Security Bulletin May 2026.
Critical Impact
A malicious app or process running with System privilege can corrupt kernel-adjacent memory through slbc, leading to local privilege escalation with full impact on confidentiality, integrity, and availability.
Affected Products
- MediaTek SoCs in the MT8xxx series, including MT8115, MT8186, MT8188, MT8196, MT8365, MT8367, MT8370, MT8371, MT8390, MT8391, MT8395, MT8676, MT8678, MT8766, MT8768, MT8775, MT8781, MT8786, MT8788E, MT8791T, MT8792, MT8793, MT8796, MT8873, MT8883, MT8893, and MT8910
- MediaTek SoCs in the MT6xxx series, including MT6899, MT6985, MT6989, and MT6991
- MediaTek MT2718 and associated firmware
Discovery Timeline
- 2026-05-04 - CVE-2026-20451 published to NVD
- 2026-05-04 - MediaTek releases security patch in the May 2026 Product Security Bulletin
- 2026-05-07 - Last updated in NVD database
Technical Details for CVE-2026-20451
Vulnerability Analysis
The vulnerability resides in the slbc (System Level Buffer Control) component shipped in MediaTek SoC firmware. The flaw is a type confusion condition that produces an out-of-bounds write when the driver interprets an object as a different type than was originally allocated. Because size and layout assumptions diverge from the actual allocation, write operations extend past the intended buffer. The attack vector is local, exploitation complexity is low, and no user interaction is required. The attacker must already operate at the System privilege level on the device.
Root Cause
The root cause is improper type handling within slbc, classified as CWE-843 (Access of Resource Using Incompatible Type — Type Confusion). When a structure pointer is reinterpreted as another type with different field offsets or sizes, subsequent member writes land outside the originally allocated region. This corrupts adjacent kernel data structures and creates a primitive suitable for privilege escalation.
Attack Vector
An attacker first establishes execution at the System privilege level on a vulnerable MediaTek device. The attacker then issues crafted requests to slbc, supplying inputs that drive the driver into the type-confused code path. The resulting out-of-bounds write modifies kernel memory and can be chained into a full privilege escalation primitive. Because the vulnerable interface is local, remote network exploitation is not in scope. See the MediaTek Security Bulletin May 2026 for vendor technical details.
Detection Methods for CVE-2026-20451
Indicators of Compromise
- Unexpected kernel panics, watchdog resets, or stability faults referencing the slbc driver in device logs
- Privileged processes spawning child processes or loading modules outside their normal behavioral baseline on MediaTek-based devices
- Presence of unsigned or unknown applications running with System privilege on affected SoC platforms
Detection Strategies
- Inventory deployed devices against the affected MediaTek SoC list and flag firmware builds that predate the May 2026 patch level
- Monitor mobile device management (MDM) telemetry for tampered or rooted devices, since System-level access is a prerequisite for exploitation
- Review crash dumps and dmesg/logcat output for repeated faults originating from slbc ioctl paths
Monitoring Recommendations
- Centralize device firmware patch-level reporting and alert on devices missing Patch ID ALPS10828685
- Track installation of applications requesting platform-signature or System-level privileges and validate provenance
- Correlate kernel-level fault telemetry with privilege-escalation behavioral indicators across the mobile fleet
How to Mitigate CVE-2026-20451
Immediate Actions Required
- Apply the MediaTek-supplied firmware update referenced by Patch ID ALPS10828685 and Issue ID MSV-6504 once the OEM publishes a device build that includes it
- Coordinate with device OEMs and carriers to confirm the May 2026 MediaTek patch level is integrated into shipping over-the-air (OTA) updates
- Restrict installation of applications that request System or platform privileges on affected devices
Patch Information
MediaTek addressed the issue in the MediaTek Security Bulletin May 2026 under Patch ID ALPS10828685 (Issue ID MSV-6504). Device manufacturers must integrate the patch into their downstream firmware images and distribute it through OTA updates. Verify the patch level on each device after update.
Workarounds
- No vendor-supplied workaround is documented; firmware update is the supported remediation
- Reduce exposure by enforcing strict app vetting and blocking sideloading on managed devices, since exploitation requires a foothold at System privilege
- Decommission or isolate devices running affected MediaTek SoCs that cannot receive the May 2026 patch level
# Verify MediaTek security patch level on an Android device
adb shell getprop ro.build.version.security_patch
adb shell getprop ro.vendor.mediatek.platform
adb shell getprop ro.boot.hardware
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
