CVE-2026-20507 in MT2718
Summary
by MITRE • 09/07/2026
In Audio HAL, there is a possible escalation of privilege 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: ALPS11191981; Issue ID: MSV-9125.
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Analysis
by VulDB Data Team • 09/07/2026
The vulnerability identified under issue identifier MSV-9125 and patch reference ALPS11191981 resides within the Audio Hardware Abstraction Layer, a critical component in Android-based operating systems that bridges high-level audio frameworks with low-level hardware drivers. This specific flaw is classified as an use-after-free condition, which represents one of the most dangerous classes of memory corruption vulnerabilities due to its potential for arbitrary code execution and privilege escalation. The root cause lies in improper management of dynamic memory allocation and deallocation within the Audio HAL subsystem. Specifically, a pointer to a previously freed memory block remains accessible or is accessed after the underlying memory has been returned to the system allocator. This creates a window where an attacker can manipulate the state of the application by writing data into that reclaimed memory space before it is reallocated for another purpose, thereby controlling program execution flow.
From a technical perspective, use-after-free vulnerabilities typically arise when developers fail to nullify pointers after freeing them or when reference counting mechanisms are flawed, leading to premature deallocation while other parts of the system still hold references to the object. In the context of an Audio HAL, this could involve audio buffers, stream objects, or callback structures that manage real-time media processing. When these structures are freed prematurely but their pointers remain valid in memory maps controlled by a higher-privileged process, it allows for heap spraying techniques or targeted overwrites. By carefully crafting input data, an attacker can overwrite function pointers, return addresses, or virtual table pointers within the reused memory block. This manipulation enables the injection and execution of arbitrary shellcode with the privileges associated with the Audio HAL service, which often operates at a high level of system trust to ensure low-latency audio processing.
The operational impact of this vulnerability is significant because it facilitates local privilege escalation. Although the prompt notes that exploitation requires the attacker to already possess System-level privileges, this scenario highlights a critical defense-in-depth failure. In many Android architectures, processes running with System UID or similar elevated permissions have access to sensitive system resources and can interact deeply with core services. If an actor has compromised such a process through another vector, they can leverage this use-after-free flaw to further escalate their rights, potentially gaining root-level control over the device. This undermines the integrity of the security model by allowing lateral movement or vertical escalation within the same trust boundary. The fact that user interaction is not required for exploitation means that if an attacker has established a foothold in a System-privileged context, they can automate this escalation without triggering any user-based alerts or requiring social engineering tactics.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-416, which defines use-after-free errors as accessing memory after it has been freed. It also maps to the MITRE ATT&CK framework under techniques related to privilege escalation and defense evasion, specifically those involving memory corruption exploitation such as T1055 or more broadly within process injection patterns depending on how the shellcode is delivered via the overwritten pointers. The absence of user interaction classifies this as a remote-code-execution-like vector if the initial foothold was achieved remotely, though here it is strictly local escalation from an already compromised high-privilege state.
Mitigation strategies for this vulnerability primarily involve rigorous code auditing and static analysis focused on memory management practices within the Audio HAL source code. Developers must ensure that all pointers are set to null immediately after being freed and implement robust reference counting mechanisms to prevent premature deallocation. Additionally, employing modern compiler protections such as Address Sanitizer during development can help detect these issues early in the lifecycle. For system administrators and device manufacturers, applying the provided patch ALPS11191981 is essential to close this gap. Furthermore, enforcing strict sandboxing policies for audio services and limiting the privileges of processes that interact with the HAL can reduce the blast radius if such a vulnerability were exploited by an external actor who had managed to gain initial access through other means. Regular security updates and proactive monitoring of system logs for anomalous memory behavior are also recommended practices to maintain resilience against these types of low-level exploits.