CVE-2023-53552 in Linux
Summary
by MITRE • 10/04/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/i915: mark requests for GuC virtual engines to avoid use-after-free
References to i915_requests may be trapped by userspace inside a sync_file or dmabuf (dma-resv) and held indefinitely across different proceses. To counter-act the memory leaks, we try to not to keep references from the request past their completion. On the other side on fence release we need to know if rq->engine is valid and points to hw engine (true for non-virtual requests). To make it possible extra bit has been added to rq->execution_mask, for marking virtual engines.
(cherry picked from commit 280410677af763f3871b93e794a199cfcf6fb580)
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Analysis
by VulDB Data Team • 03/02/2026
The vulnerability described in CVE-2023-53552 affects the Linux kernel's graphics subsystem, specifically within the i915 driver that manages Intel graphics hardware. This issue represents a use-after-free condition that can occur when handling graphics requests submitted to GuC virtual engines, which are part of Intel's Graphics User Control (GuC) firmware architecture designed to improve graphics processing efficiency. The vulnerability arises from improper handling of request references that may be held by userspace applications through synchronization mechanisms.
The technical flaw stems from how the kernel manages references to graphics requests within the i915 driver's request tracking system. When graphics requests are submitted to GuC virtual engines, they may be trapped by userspace applications and held indefinitely through sync_file or dmabuf (dma-resv) mechanisms. These synchronization objects can maintain references to request structures across different processes, creating a scenario where request objects may be freed while still being referenced elsewhere in the system. The traditional approach of tracking request completion through request structures becomes problematic when virtual engines are involved, as the relationship between request objects and their underlying hardware execution engines becomes more complex.
The operational impact of this vulnerability extends beyond simple memory management issues to potentially enable arbitrary code execution or system instability. When the kernel attempts to release fence objects, it needs to validate whether the request's engine field points to a valid hardware engine. For non-virtual requests, this validation is straightforward, but for virtual requests, the kernel must distinguish between different engine types to prevent accessing freed memory locations. Without proper marking of virtual engine requests, the kernel may attempt to access invalid memory locations during fence cleanup operations, leading to system crashes or potential privilege escalation.
The fix implemented addresses this issue by adding an extra bit to the request's execution_mask field specifically for marking virtual engines. This modification enables the kernel to properly distinguish between virtual and hardware engine requests during fence release operations, preventing the use-after-free scenario. The solution follows established security practices for memory management in kernel space, ensuring that objects are not accessed after being freed while maintaining compatibility with existing userspace applications that rely on synchronization mechanisms. This approach aligns with common security patterns for preventing use-after-free vulnerabilities and demonstrates proper defensive programming techniques in kernel development.
This vulnerability type corresponds to CWE-416, which describes the use of freed memory condition, and relates to the broader category of memory safety issues in kernel space. The fix implementation follows security best practices for kernel memory management and demonstrates the importance of proper reference counting and object lifecycle management in operating system kernels. The solution also reflects the ATT&CK framework's approach to kernel-level vulnerabilities, particularly in the context of privilege escalation and system stability attacks that could be exploited by malicious actors with access to graphics subsystems. The cherry-picked commit from the kernel's source tree indicates this is a well-tested and integrated fix that addresses the specific memory management challenges inherent in virtual engine implementations within the Intel graphics driver ecosystem.