CVE-2026-68427 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
gpu: host1x: Fix use-after-free in host1x_bo_clear_cached_mappings
__host1x_bo_unpin() drops the last reference to the mapping and frees it, so we can't dereference mapping afterwards. The cache itself outlives the mapping, so use the cache local variable instead.
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Analysis
by VulDB Data Team • 08/10/2026
This vulnerability represents a classic use-after-free condition affecting the host1x graphics subsystem within the Linux kernel. The issue occurs in the gpu host1x driver where the __host1x_bo_unpin() function handles memory buffer object cleanup operations. When this function executes, it releases the final reference to a memory mapping structure and subsequently frees that mapping from memory. However, the code path continues to attempt dereferencing the freed mapping pointer rather than using the cache variable that maintains the necessary information. This type of vulnerability falls under the CWE-416 category for use-after-free conditions, which is particularly dangerous in kernel space where such flaws can lead to privilege escalation or system instability. The host1x subsystem is designed to manage graphics buffer objects for embedded systems and mobile platforms, making this vulnerability relevant to automotive infotainment systems, mobile devices, and other embedded computing environments that rely on NVIDIA's tegra graphics processing units.
The technical flaw manifests in the memory management sequence of the host1x driver where the mapping structure undergoes deallocation while the code continues to reference it through a dangling pointer. The cache variable mentioned in the fix contains the necessary data that should be used instead of the freed mapping structure, demonstrating the importance of proper resource lifecycle management in kernel space operations. This pattern violates fundamental security principles where developers must ensure that memory references are valid before dereferencing them. The vulnerability is particularly concerning because it occurs during buffer object unpinning operations which are frequent activities in graphics processing workloads, meaning the attack surface is actively utilized during normal system operation.
Operationally, this use-after-free vulnerability could enable malicious actors to execute arbitrary code with kernel privileges if exploited successfully. The impact extends beyond simple system crashes to potentially allow privilege escalation attacks that could compromise the entire system. Attackers might leverage this flaw in scenarios involving graphics-intensive applications or when exploiting other vulnerabilities in the same subsystem. The timing of the vulnerability during buffer object cleanup operations makes it particularly dangerous as it could be triggered through normal graphics processing activities, potentially allowing for persistent exploitation. This aligns with ATT&CK technique T1068 which covers local privilege escalation and T1547 which addresses persistence mechanisms through kernel-level modifications.
The recommended mitigation strategy involves applying the upstream kernel patch that corrects the reference pattern by using the cache variable instead of the freed mapping pointer. System administrators should prioritize updating to kernel versions containing this fix, particularly in production environments where graphics processing is intensive. Monitoring for unusual system behavior or kernel panic messages related to host1x operations can help detect potential exploitation attempts. Additionally, implementing proper kernel memory debugging tools like kmemcheck or enabling kernel address space layout randomization (KASLR) can provide additional protection layers against such vulnerabilities. Organizations should also consider reducing the attack surface by disabling unnecessary graphics drivers or using more restrictive security policies for graphics-related applications.