CVE-2026-68259 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Check bounds in allocate_event_notification_slot
The valid event ids go from 0 to KFD_SIGNAL_EVENT_LIMIT
allocate_event_notification_slot has an option to specify an event id to allocate at, used by CRIU. We weren't checking the bounds on that value.
Check them.
v2: Lower bounds check is unecessary because of idr_alloc already rejecting negative numbers. Upper bounds check should be KFD_SIGNAL_EVENT_LIMIT since the signal mode mappings might not yet exist
(cherry picked from commit 6853f1f6cbbeb3f53ebbbd7286536aeb2c5d5f50)
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability in question affects the Linux kernel's graphics subsystem, specifically within the amdkfd driver component that manages AMD GPU compute functionality. This issue resides in the drm/amdkfd module where event notification slots are allocated for GPU compute operations. The flaw represents a classic buffer overflow condition that could potentially allow malicious actors to manipulate memory structures through improper input validation.
The technical implementation involves the allocate_event_notification_slot function which accepts an event identifier parameter used by CRIU (Checkpoint/Restore in Userspace) functionality for managing GPU state during system migration operations. The vulnerability stems from insufficient bounds checking on the event id parameter, creating a scenario where values outside the acceptable range of 0 to KFD_SIGNAL_EVENT_LIMIT could be processed without validation. This oversight allows for potential memory corruption or unauthorized access patterns that could compromise system integrity.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a privilege escalation vector within the GPU compute subsystem. When CRIU attempts to allocate event notification slots during checkpoint operations, malicious input could cause the kernel to write data beyond allocated memory boundaries, potentially leading to arbitrary code execution or system crashes. The vulnerability affects systems utilizing AMD GPUs with compute capabilities and is particularly concerning given the widespread use of CRIU in containerized environments and cloud computing platforms.
Security implications align with CWE-129 Input Validation and CWE-787 Out-of-bounds Write categories, where improper validation of input parameters leads to memory corruption vulnerabilities. The issue demonstrates poor defensive programming practices in kernel space where input validation should occur at multiple levels before any processing begins. From an attack perspective, this vulnerability maps to ATT&CK technique T1068, as it provides a path for privilege escalation through kernel memory corruption. The fix implemented addresses both the upper bounds check with proper validation against KFD_SIGNAL_EVENT_LIMIT and removes unnecessary lower bounds checks since the underlying idr_alloc function already handles negative number rejection, demonstrating proper understanding of the existing system architecture.
Mitigation strategies should include immediate deployment of the kernel patch addressing this specific issue, alongside broader security monitoring for anomalous GPU compute operations that might indicate exploitation attempts. System administrators should also consider implementing kernel hardening measures such as KASAN (Kernel Address Sanitizer) and KPTI (Kernel Page Table Isolation) to detect and prevent similar vulnerabilities in other kernel subsystems. Regular kernel updates remain critical, as this vulnerability represents a typical example of how seemingly minor input validation gaps can create significant security risks in complex operating system components, particularly those handling hardware-specific compute operations that require precise memory management and access control.