CVE-2026-43396 in Linux
Summary
by MITRE • 05/08/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/xe/sync: Fix user fence leak on alloc failure
When dma_fence_chain_alloc() fails, properly release the user fence reference to prevent a memory leak.
(cherry picked from commit a5d5634cde48a9fcd68c8504aa07f89f175074a0)
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Analysis
by VulDB Data Team • 09/13/2026
This vulnerability resides within the graphics subsystem of the Linux kernel, specifically affecting the x86 graphics execution (xe) driver's synchronization mechanisms. The issue manifests as a memory leak occurring when the dma_fence_chain_alloc() function encounters allocation failure during user fence operations. The root cause lies in improper resource management where the user fence reference is not properly released when the allocation process fails, leading to persistent memory consumption that can accumulate over time and potentially impact system stability.
The technical flaw represents a classic resource leak pattern that aligns with CWE-404, which categorizes improper resource management as a fundamental weakness in software design. When the dma_fence_chain_alloc() function fails to allocate necessary memory structures for fence synchronization, the subsequent failure to release the associated user fence reference creates a dangling pointer scenario. This type of memory leak occurs within the kernel's graphics execution context, where synchronization objects are crucial for coordinating graphics operations between different hardware components and user-space applications.
The operational impact of this vulnerability extends beyond simple memory consumption issues, as it can degrade system performance and potentially lead to system instability under sustained graphics workloads. Graphics drivers in kernel space operate with elevated privileges and handle critical system resources, making memory leaks particularly dangerous as they can accumulate over time and eventually exhaust available memory resources. The vulnerability affects systems utilizing the xe graphics driver, which is commonly found in modern Intel graphics implementations and can impact various applications requiring graphics acceleration including desktop environments, video playback software, and graphics-intensive applications.
Mitigation strategies should focus on ensuring proper error handling and resource cleanup mechanisms within the kernel graphics subsystem. System administrators should apply the patched kernel version containing the cherry-picked commit a5d5634cde48a9fcd68c8504aa07f89f175074a0 to address the specific memory leak issue. The fix implements proper reference counting and cleanup procedures when allocation failures occur, preventing the accumulation of unreleased user fence objects. Organizations should also implement monitoring solutions to detect memory consumption patterns that might indicate similar resource leak vulnerabilities in other kernel components. This vulnerability demonstrates the importance of robust error handling in kernel space operations and aligns with ATT&CK technique T1068 which involves privilege escalation through kernel vulnerabilities, though this particular issue primarily manifests as resource exhaustion rather than direct privilege escalation.