CVE-2026-20581 in MT6858
Summary
by MITRE • 11/02/2026
In usb, there is a possible memory corruption due to use after free. This could lead to local escalation of privilege if a malicious actor has already obtained the System privilege. User interaction is not needed for exploitation. Patch ID: ALPS11411985; Issue ID: MSV-9750.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 11/02/2026
The vulnerability described involves a critical memory management flaw within the Universal Serial Bus subsystem, specifically characterized as a use-after-free condition. This type of defect occurs when software continues to reference a pointer after the memory it points to has been deallocated or freed by another part of the system. In the context of USB device handling, this typically manifests during the lifecycle management of driver objects or data structures associated with connected peripherals. When a malicious actor interacts with a compromised or specially crafted USB device, they can trigger specific code paths that free critical memory resources prematurely while other parts of the kernel still hold references to those same addresses. This creates a window where the system may read from or write to invalid memory locations, leading to undefined behavior and potential corruption of adjacent data structures in the kernel heap.
From an operational perspective, this vulnerability represents a significant security risk because it allows for local privilege escalation under specific conditions. The description notes that exploitation requires the attacker to already possess System privileges, which might seem contradictory at first glance since System is typically the highest level of access on many operating systems. However, in complex multi-tenant environments or virtualized contexts where different processes run with varying levels of isolation, gaining initial foothold as a lower-privileged user who can then escalate to full system control via this flaw would be catastrophic. Alternatively, if the attacker has already achieved System-level execution through another vector, manipulating memory corruption could allow them to bypass security controls such as kernel patch protection or integrity checks that rely on specific memory states remaining consistent and uncorrupted. The absence of user interaction further lowers the barrier for exploitation, making this a high-severity issue suitable for automated attacks via physically connected malicious hardware devices like BadUSB variants or compromised peripherals designed to exploit driver bugs upon connection.
The technical classification of this flaw aligns closely with Common Weakness Enumeration identifier CWE-416, which defines use-after-free errors as situations where pointers are used after they have been freed, often leading to crashes, data corruption, and arbitrary code execution. The attack vector is categorized under ATT&CK technique T1059, specifically Command and Scripting Interpreter or potentially T1203 if it involves exploitation for binary execution, but more accurately fits within the broader category of Exploitation for Privilege Escalation (T1068) when considering the outcome. The physical attack surface is expanded through USB interfaces, which are often left unsecured in many enterprise and consumer environments due to convenience factors like auto-mounting or automatic driver installation features that do not sufficiently validate input from external devices before processing them within privileged kernel space.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. The primary remediation is the application of Patch ID ALPS11411985, which addresses the specific memory management logic flaw in the USB driver stack. Organizations should prioritize deploying this update across all endpoints that utilize affected components to close the window for exploitation. Beyond patching, defensive measures include disabling automatic execution and auto-mount features for removable media where feasible, enforcing strict device control policies through endpoint detection and response solutions, and implementing hardware-based restrictions such as port-level access controls in high-security environments. Additionally, enabling kernel memory protection mechanisms like Kernel Address Space Layout Randomization and Data Execution Prevention can mitigate the impact of successful exploitation by making it significantly harder to predict memory layouts or execute shellcode within the corrupted regions. Continuous monitoring for anomalous USB device connections and unusual privilege escalation attempts will also aid in detecting potential exploitation activities even if patches are delayed.