CVE-2026-20558 in MT6993
Summary
by MITRE • 11/02/2026
In GPU pdma, there is a possible escalation of privilege due to use after free. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS11365070; Issue ID: MSV-9547.
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Analysis
by VulDB Data Team • 11/02/2026
The vulnerability identified under issue identifier MSV-9547 and addressed by patch ALPS11365070 represents a critical security flaw within the GPU peripheral direct memory access subsystem, commonly referred to as pdma in this context. This specific defect is classified technically as a use-after-free error, which falls squarely under the Common Weakness Enumeration category CWE-416. In modern computing architectures, particularly those involving complex graphics processing units and their associated hardware accelerators, efficient memory management is paramount for maintaining system stability and security. The pdma subsystem facilitates high-speed data transfers between main memory and GPU components without continuous CPU intervention. However, the flaw arises when the software manages pointers to freed memory regions incorrectly, allowing access to these deallocated blocks after they have been returned to the operating system or hardware allocator for reuse by other processes or kernel structures.
The technical mechanism behind this vulnerability involves a failure in reference counting or pointer invalidation within the pdma driver logic. When a data structure associated with a DMA transaction is freed, the corresponding pointers are not properly nullified or removed from active tracking lists. Consequently, if subsequent operations attempt to access these memory locations based on stale references, they may read sensitive information or, more critically, write maliciously crafted data into arbitrary kernel memory addresses. This scenario creates an opportunity for heap corruption and control flow hijacking. Since the vulnerability exists within a core system component that operates with high privileges, successful exploitation allows an attacker to execute code in ring 0, effectively gaining full administrative control over the operating system without requiring any special hardware permissions or elevated user rights initially.
From an operational perspective, this flaw enables local privilege escalation, meaning that any unprivileged user account on the affected device can potentially exploit this condition to gain root or SYSTEM-level access. The attack vector is classified as adjacent because it typically requires physical proximity or direct console access to the machine, although in virtualized environments or shared hosting scenarios, remote exploitation might be possible if the guest OS has direct hardware passthrough capabilities. Notably, no user interaction is required for exploitation, which significantly lowers the barrier for attackers and increases the likelihood of automated attacks targeting vulnerable systems. This characteristic aligns with ATT&CK technique T1068 Exploitation for Privilege Escalation, specifically highlighting how memory corruption vulnerabilities are leveraged to bypass standard access controls.
The impact of this vulnerability is severe as it compromises the integrity, confidentiality, and availability of the entire system. An attacker who successfully exploits this use-after-free condition can install malware, create backdoors, steal sensitive data such as encryption keys or user credentials, and disable security software protections. Because GPU drivers often handle large buffers containing potentially sensitive graphical data or compute results, there is also a risk of information disclosure beyond just privilege escalation. The lack of required execution privileges means that even sandboxed applications with limited permissions could serve as the initial foothold for launching this attack, making it particularly dangerous in multi-user environments or mobile devices where multiple apps run concurrently.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. The primary remediation is to apply the vendor-provided patch ALPS11365070 immediately across all affected systems. This update likely includes fixes for pointer invalidation, enhanced bounds checking, and improved memory lifecycle management within the pdma subsystem. Beyond applying patches, system administrators should enforce strict least-privilege principles, ensuring that user accounts have only the minimum permissions necessary to perform their tasks. Implementing kernel hardening features such as Kernel Address Space Layout Randomization (KASLR), Data Execution Prevention (DEP), and Control Flow Guard can help mitigate the impact of exploitation attempts by making it harder for attackers to predict memory layouts or execute injected code. Additionally, regular security audits and static analysis tools focused on detecting use-after-free patterns in driver development processes are essential preventive measures against similar vulnerabilities in future software releases.