CVE-2026-20591 in MT6993
Summary
by MITRE • 11/02/2026
In GPU pdma, there is a possible escalation of privilege due to a missing permission check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS11365075; Issue ID: MSV-9546.
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Analysis
by VulDB Data Team • 11/02/2026
The vulnerability identified under issue identifier MSV-9546 and addressed by patch ALPS11365075 represents a critical security flaw within the GPU peripheral direct memory access subsystem, commonly referred to as pdma in this context. This component is responsible for managing data transfers between system memory and graphics processing units without continuous intervention from the central processor. The core technical deficiency lies in an absent permission check during these operations, which allows processes with lower privilege levels to bypass standard security controls designed to restrict access to sensitive kernel resources or protected memory regions. In a properly secured operating environment, any attempt by a user-space application to initiate direct memory access must be validated against the current process credentials and system policy constraints. The absence of this validation mechanism creates an open pathway for unauthorized interaction with hardware-level functions that should remain isolated from untrusted software contexts.
This architectural oversight directly facilitates local privilege escalation, allowing an attacker who has already gained a foothold within the operating system to elevate their access rights to those of the kernel or root user. Because the exploitation does not require additional execution privileges beyond what is typically granted to standard applications, and because it operates without any need for user interaction such as clicking prompts or opening specific files, the attack surface is significantly expanded. An attacker can potentially execute arbitrary code with high-level system permissions simply by crafting a malicious request that triggers the pdma subsystem's flawed logic. This characteristic makes the vulnerability particularly dangerous in multi-user environments or on devices where multiple applications run concurrently, as even sandboxed apps might leverage this flaw to break out of their restricted execution contexts and compromise the entire host system.
From a classification perspective, this issue aligns closely with CWE-269, which denotes Improper Privilege Management, specifically regarding the failure to enforce required permissions before performing sensitive operations. Furthermore, in terms of offensive security frameworks such as MITRE ATT&CK, this vulnerability supports techniques associated with privilege escalation on local systems, potentially mapping to tactics like Defense Evasion or Command and Control if used to establish persistent high-level access. The lack of input validation regarding the requesting process's authority level is a fundamental design error that undermines the principle of least privilege, which dictates that every module should operate using only the minimum set of privileges necessary for its function.
Mitigation strategies must prioritize the immediate application of the provided patch ALPS11365075 to restore proper access control checks within the pdma subsystem. Beyond software updates, system administrators and developers should implement strict memory isolation techniques such as hardware-enforced virtualization or sandboxing to limit the blast radius if a similar flaw is discovered in other components. Regular security audits focusing on kernel-mode drivers and hardware abstraction layers are essential to identify missing permission validations before they can be exploited. Additionally, enabling advanced monitoring solutions that detect anomalous direct memory access patterns from low-privilege processes can provide early warning indicators of exploitation attempts, allowing for rapid incident response even if patching is temporarily delayed due to operational constraints.