CVE-2020-0069: Mediatek Multiple Chipsets Insufficient Input Validation Vulnerability

CVE-2020-0069 is an insufficient input validation flaw in multiple MediaTek chipsets that can produce an out-of-bounds write in Command Queue driver ioctl handlers, combined with missing SELinux restrictions. The result is local privilege escalation on devices that use the affected silicon. It matters because the issue was observed in the wild as part of the “AbstractEmu” exploit chain that also leveraged CVE-2019-2215 and CVE-2020-0041, giving attackers a reliable path from a lower-privilege foothold to higher system privileges on vulnerable Android and other MediaTek-based platforms.

Organizations that manage fleets of mobile devices, IoT endpoints, or embedded systems built on MediaTek hardware should treat this as a high-priority local-escalation risk until they confirm their chipset firmware and driver stacks are patched.

How it works

The weakness is classified as CWE-787 (out-of-bounds write). In the Command Queue drivers, ioctl handlers fail to validate input thoroughly and lack the SELinux restrictions that would normally confine the driver’s privileges. An attacker who can already execute code on the device (for example after a browser or app compromise) supplies crafted input to these handlers. Because bounds are not enforced, the write lands outside the intended buffer, corrupting kernel or driver memory and allowing the attacker to elevate privileges.

Public detail on the exact ioctl numbers or memory layout is limited; defenders should treat any untrusted local process that can open the Command Queue device nodes as a potential abuse vector. The vulnerability was chained with two other Android kernel issues under the AbstractEmu campaign, illustrating that a single out-of-bounds write can become part of a multi-stage privilege-escalation sequence.

Am I affected? How to find it in your systems

MediaTek chipsets appear in a wide range of Android smartphones, tablets, set-top boxes, and embedded devices. Inventory steps:

• Query device management or MDM inventories for hardware that reports a MediaTek SoC (commonly visible in build.prop, /proc/cpuinfo, or vendor-specific sysfs nodes).
• Cross-reference the chipset model and firmware revision against the vendor security bulletin that addresses CVE-2020-0069; exact affected part numbers and versions are published only by MediaTek and OEMs, so confirm against those advisories.
• On rooted or lab devices, inspect loaded kernel modules and device nodes related to Command Queue / CMDQ drivers; presence of the unpatched driver is an indicator of exposure.
• Review kernel logs (dmesg, logcat with kernel buffer) for unexpected ioctl failures, SELinux denials, or crashes in CMDQ-related paths that could signal attempted exploitation. No unique ransomware signature is documented for this CVE alone.

How to remediate

Apply the vendor-supplied updates that remediate CVE-2020-0069 as soon as they are available for your device models. CISA’s required action is simply “Apply updates per vendor instructions.” OEMs typically distribute the fix through over-the-air firmware or full system-image releases; enterprise fleets should push the update via MDM and verify successful installation by checking the new security patch level or firmware build string.

After patching, re-enable any SELinux enforcing mode that may have been temporarily relaxed, and confirm that the Command Queue driver now enforces proper input validation and confinement. For custom or long-lifecycle embedded products, obtain the updated MediaTek BSP or driver package directly from the silicon vendor and rebuild the kernel image.

If you can't patch immediately

Until the official update can be deployed:

• Segment affected devices onto restricted network zones so that a compromised handset cannot reach high-value internal resources.
• Enforce strict application allow-listing and disable unnecessary local services that could give an attacker the initial code-execution foothold needed to reach the vulnerable ioctls.
• If a host-based or network virtual-patching capability exists for the Android kernel attack surface, enable signatures that detect anomalous ioctl patterns against CMDQ device nodes; treat this only as a temporary bridge.
• Increase monitoring of privilege-escalation indicators (unexpected uid 0 processes, SELinux AVC denials involving CMDQ, kernel oopses) and forward them to the SOC for rapid triage.
• Where the product architecture allows, unload or blacklist the Command Queue driver if the feature is not required for normal operation—confirm impact with the device vendor first.

If your data may have been exposed

Actively exploited local-privilege-escalation chains such as AbstractEmu can lead to full device compromise and subsequent data theft. If you suspect devices were targeted, isolate them, capture forensic images, and rotate credentials that may have been accessible from the handset. You can also run a free exposure scan of your email addresses against known breach data sets to determine whether related accounts have already appeared in public dumps.