CVE-2026-68380 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
accel/amdxdna: Fix use-after-free of mm_struct in job scheduler
amdxdna_cmd_submit() stores current->mm in job->mm without holding any reference. aie2_sched_job_run() later access job->mm from the DRM scheduler worker thread. With only a raw pointer and no structural reference, the mm_struct can be freed before the scheduler runs the job.
Fix this by calling mmgrab() to hold a structural mm_count reference for the lifetime of the job, paired with mmdrop() in every cleanup path.
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability identified in the Linux kernel's amdxdna driver represents a critical use-after-free condition that occurs within the job scheduling mechanism of the Accelerated Compute (accel) subsystem. This flaw manifests specifically in the interaction between the amdxdna_cmd_submit function and the aie2_sched_job_run function, creating a scenario where memory corruption can occur during concurrent execution. The issue stems from improper reference handling when storing memory management structures during job submission processes.
The technical root cause involves the amdxdna_cmd_submit() function which captures the current process's memory management structure current->mm and stores it directly within the job->mm field without establishing any protective references. This raw pointer assignment creates a dangerous race condition where the mm_struct can be freed by the kernel's memory management subsystem while the job remains queued for execution. The subsequent aie2_sched_job_run() function accesses this stored pointer from a dedicated DRM scheduler worker thread context, leading to undefined behavior when attempting to dereference a freed memory structure.
This vulnerability directly maps to CWE-416, which describes use-after-free conditions in software systems, and represents a classic example of improper reference counting in kernel space programming. The operational impact extends beyond simple memory corruption as it can lead to system instability, potential privilege escalation, and denial of service conditions within systems utilizing AMD XDNA hardware acceleration capabilities. The vulnerability affects any system running the Linux kernel with active amdxdna drivers where job scheduling occurs concurrently with memory management operations.
The fix implemented addresses this issue by introducing proper reference counting mechanisms through the mmgrab() function call during job submission, which establishes a structural reference that prevents premature deallocation of the mm_struct. This structural reference is maintained throughout the job's lifecycle and properly released via mmdrop() in all cleanup paths to ensure consistent resource management. The solution aligns with established kernel security practices for managing memory management structures in concurrent environments and follows ATT&CK technique T1068 by preventing unauthorized privilege escalation through memory corruption vulnerabilities.
This remediation approach ensures that memory management structures remain valid during job execution while maintaining proper resource accounting throughout the kernel's memory subsystem. The fix demonstrates proper kernel programming practices for handling shared resources across different execution contexts and prevents potential exploitation scenarios where attackers could leverage this use-after-free condition to execute arbitrary code or compromise system integrity. The implementation maintains backward compatibility while strengthening the security posture of the AMD XDNA acceleration framework against memory safety vulnerabilities.