CVE-2026-58926 in Android
Summary
by MITRE • 11/02/2026
A Use-After-Free (UAF) vulnerability exists in the EVS HAL, allowing a privileged client to free a `buffer_handle_t` while the producer thread is still using it. This race condition, triggered via `doneWithFrame` and `setMaxFramesInFlight`, enables an attacker to manipulate freed heap memory, potentially leading to the leakage of file descriptors from the EVS HAL process.
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Analysis
by VulDB Data Team • 11/02/2026
The vulnerability identified in the Video Encoder/Decoder Hardware Abstraction Layer (EVS HAL) represents a critical Use-After-Free condition rooted in improper synchronization mechanisms within the multimedia processing pipeline. This flaw allows an attacker with privileged access to manipulate memory states during frame buffer management operations. Specifically, the race condition is triggered through interactions between the `doneWithFrame` and `setMaxFramesInFlight` API calls. These functions are central to managing the lifecycle of video frames as they move from production to consumption stages within the HAL. The core technical flaw lies in the failure to properly synchronize access to shared resources, specifically the buffer handles represented by `buffer_handle_t`. When a privileged client invokes these methods without adequate locking or atomicity guarantees, it creates a window where memory can be deallocated while still being actively referenced by another thread, namely the producer thread responsible for capturing and processing video frames.
From a technical perspective, this vulnerability exploits the asynchronous nature of multimedia HAL operations. The `setMaxFramesInFlight` function typically controls how many buffers are allowed to exist in the pipeline simultaneously, influencing memory allocation patterns. Meanwhile, `doneWithFrame` signals that a specific frame has been processed and its resources can be released. If these two operations occur concurrently without strict mutual exclusion, an attacker can force the system to free a buffer handle while the producer thread is still attempting to access or modify it. This results in a classic Use-After-Free scenario where the memory previously occupied by the valid buffer handle becomes available for reallocation. Because heap memory allocation algorithms often reuse recently freed blocks, subsequent allocations may return pointers to this same memory region. An attacker can then write controlled data into these newly allocated structures, effectively overwriting critical metadata or control flow information associated with the original buffer context.
The operational impact of this vulnerability extends beyond simple application crashes or denial-of-service conditions. The primary consequence highlighted in the analysis is the potential leakage of file descriptors from the EVS HAL process. In Android and similar embedded Linux environments, file descriptor tables are sensitive structures that map integer identifiers to open files, sockets, or hardware devices. By manipulating freed heap memory through this race condition, an attacker can corrupt these mappings or read adjacent memory regions containing such information. This leakage provides a foothold for further exploitation, as access to specific file descriptors can allow the attacker to interact with other system components, escalate privileges by accessing sensitive files, or pivot into more critical subsystems within the device architecture. The ability to leak internal process state significantly lowers the barrier for subsequent attacks that rely on understanding the memory layout and resource allocation strategies of the HAL daemon.
This vulnerability aligns closely with CWE-416, which defines Use-After-Free as a flaw occurring when software uses memory after it has been freed, often leading to crashes or arbitrary code execution. Furthermore, in the context of the MITRE ATT&CK framework for mobile platforms, this behavior relates to techniques involving resource manipulation and potential privilege escalation through improper handling of system resources. The exploitation vector requires privileged access initially, which limits its applicability against untrusted apps but makes it highly dangerous if compromised by a malicious application with elevated permissions or via kernel-level exploits that gain such privileges.
Mitigation strategies must focus on enforcing strict synchronization protocols within the EVS HAL implementation. Developers should implement robust locking mechanisms around all accesses to shared buffer handles and frame state variables to ensure atomicity between `doneWithFrame` and `setMaxFramesInFlight`. Additionally, employing smart pointer semantics or reference counting with careful lifetime management can prevent premature deallocation of resources still in use by other threads. Static analysis tools configured to detect race conditions and memory safety violations should be integrated into the development pipeline to identify such synchronization flaws early. For system administrators, ensuring that only trusted applications are granted privileged access to HAL interfaces reduces the attack surface significantly. Regular security audits focusing on multimedia subsystems are essential given their complexity and historical prevalence of similar vulnerabilities in Android-based ecosystems.