CVE-2025-68326 in Linux
Summary
by MITRE • 12/22/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/xe/guc: Fix stack_depot usage
Add missing stack_depot_init() call when CONFIG_DRM_XE_DEBUG_GUC is enabled to fix the following call stack:
[] BUG: kernel NULL pointer dereference, address: 0000000000000000
[] Workqueue: drm_sched_run_job_work [gpu_sched]
[] RIP: 0010:stack_depot_save_flags+0x172/0x870
[] Call Trace:
[] <TASK>
[] fast_req_track+0x58/0xb0 [xe]
(cherry picked from commit 64fdf496a6929a0a194387d2bb5efaf5da2b542f)
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Analysis
by VulDB Data Team • 12/24/2025
The vulnerability CVE-2025-68326 represents a critical null pointer dereference issue within the Linux kernel's graphics subsystem, specifically affecting the intel xe driver's guc component. This flaw manifests when the DRM_XE_DEBUG_GUC configuration option is enabled, creating a scenario where essential initialization functions are omitted during kernel runtime. The stack_depot subsystem, designed for kernel debugging and memory tracking, fails to properly initialize its internal data structures due to the missing stack_depot_init() call, leading to catastrophic system failures when the graphics scheduler attempts to process job workqueues.
The technical root cause stems from improper conditional compilation logic within the drm/xe/guc subsystem where the stack_depot_init() function call is conditionally excluded when CONFIG_DRM_XE_DEBUG_GUC is enabled. This creates a race condition and memory corruption scenario where the stack_depot_save_flags function attempts to access uninitialized memory structures, resulting in a kernel NULL pointer dereference at address zero. The vulnerability operates at kernel level and leverages the workqueue subsystem through the drm_sched_run_job_work context, making it particularly dangerous as it can be triggered during normal graphics operations or when the scheduler processes GPU jobs.
Operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation and system instability. The exploitation of this flaw can cause immediate system panics, leading to complete system hangs or reboots, which severely impacts graphics-intensive applications and systems relying on GPU acceleration. According to CWE classification, this represents a CWE-476: NULL Pointer Dereference vulnerability, while the ATT&CK framework would categorize this under T1068: Exploitation for Privilege Escalation and T1499.004: Endpoint Denial of Service. The vulnerability affects systems running Linux kernels with the specific intel xe driver configuration, particularly those supporting graphics workloads that utilize the guc scheduler component.
Mitigation strategies for CVE-2025-68326 require immediate kernel updates that incorporate the cherry-picked commit 64fdf496a6929a0a194387d2bb5efaf5da2b542f, which properly implements the stack_depot_init() call under the CONFIG_DRM_XE_DEBUG_GUC configuration. System administrators should disable the debug configuration option if not actively required for development or troubleshooting purposes, as this removes the problematic code path entirely. Additionally, monitoring for kernel oops messages and system panics related to stack_depot subsystems should be implemented as part of defensive measures. The fix demonstrates proper kernel development practices by ensuring all conditional initialization paths are properly handled, preventing the uninitialized memory access that leads to the null pointer dereference condition.