CVE-2026-74416 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/radeon: fix memory leak in radeon_ring_restore() on lock failure
radeon_ring_restore() takes ownership of the data buffer allocated by radeon_ring_backup(). The caller (radeon_gpu_reset()) only frees it in the non-restore branch; in the restore branch it relies on radeon_ring_restore() to free it.
If radeon_ring_lock() fails, the function returned early without calling kvfree(data), leaking the ring backup buffer on every GPU reset that fails at the lock stage. During repeated GPU resets this causes cumulative kernel memory exhaustion.
Free data before returning the error.
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Analysis
by VulDB Data Team • 08/15/2026
This vulnerability resides within the radeon graphics driver component of the linux kernel and represents a classic memory management flaw that can lead to progressive resource exhaustion. The issue manifests in the drm/radeon subsystem where the radeon_ring_restore() function is responsible for handling gpu reset operations and managing ring buffer data structures. The core problem emerges from improper ownership semantics between the radeon_gpu_reset() caller and the radeon_ring_restore() callee, creating a scenario where memory allocated by one function is not properly released by another. When radeon_ring_lock() fails during the restoration process, the function exits prematurely without executing the necessary cleanup operation of freeing the data buffer that was allocated by radeon_ring_backup(). This failure to release memory creates a persistent leak that accumulates with each failed gpu reset attempt, ultimately leading to kernel memory exhaustion and system instability.
The technical flaw directly violates fundamental memory management principles and can be categorized under CWE-401 as improper deallocation of memory, specifically manifesting as a memory leak in kernel space. The vulnerability operates at the intersection of resource management and error handling within the graphics driver stack, where the expected flow of ownership between functions breaks down during exceptional conditions. The radeon_ring_restore() function assumes responsibility for freeing the data buffer but fails to do so when lock acquisition fails, while the caller radeon_gpu_reset() only frees the buffer in non-restore code paths. This creates a conditional memory leak that occurs specifically when gpu reset operations encounter locking failures during the restoration phase, which can happen under various stress conditions or resource contention scenarios.
The operational impact of this vulnerability extends beyond simple memory consumption issues to potentially compromise system stability and availability. When repeated gpu resets fail at the lock stage, the cumulative effect of leaked memory buffers can exhaust available kernel memory resources, leading to system slowdowns, application crashes, or even complete system hangs. The vulnerability is particularly concerning in environments with high graphics workloads or frequent gpu reset operations where the memory leak compounds rapidly. From an attacker perspective, this represents a potential denial of service vector that could be exploited through repeated gpu reset attempts, though the practical exploitation requires specific conditions and may be limited by system configurations. The issue aligns with ATT&CK technique T1490 for resource exhaustion and demonstrates how kernel-level memory management flaws can create persistent stability issues.
The mitigation strategy involves implementing proper error handling in radeon_ring_restore() to ensure that allocated data buffers are freed regardless of the function's success or failure status. This requires modifying the early return path when radeon_ring_lock() fails to include the necessary cleanup operation of calling kvfree(data) before returning the error code. The fix ensures that memory ownership is properly transferred and released according to the established contract between the two functions, preventing the accumulation of leaked buffers during failed gpu reset operations. This approach follows standard kernel programming practices for resource management and error handling, ensuring that all allocated resources are properly accounted for and freed even in exceptional conditions. The solution maintains the existing functionality while addressing the memory leak through proper cleanup in error paths, aligning with the principle of defensive programming and robust resource management in kernel space operations.
The vulnerability highlights broader concerns about memory management practices within graphics driver subsystems and the importance of maintaining clear ownership semantics between functions. It demonstrates how seemingly isolated failures in lock acquisition can cascade into system-wide resource exhaustion issues, emphasizing the need for comprehensive error handling in kernel code. The fix serves as a reminder of the critical nature of proper resource cleanup in kernel space where memory leaks can have severe consequences for system stability and performance. This type of vulnerability is particularly relevant in modern computing environments where graphics processing is increasingly critical for both desktop and server workloads, making robust memory management essential for maintaining system reliability and preventing potential exploitation scenarios.