CVE-2026-72244 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
gpu/buddy: bail out of try_harder when alignment cannot be honoured
The try_harder contiguous fallback could return a range whose start offset did not match the caller's min_block_size. When a candidate's start is misaligned, realign it: free the misaligned run and reallocate exactly @size at the next lower min_block_size boundary. This keeps the returned size unchanged with no surplus to trim, and rejects the request only when no aligned candidate fits.
v2: align misaligned candidates down to min_block_size instead of bailing out, for both the RHS and LHS paths (Matthew).
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Analysis
by VulDB Data Team • 08/15/2026
This vulnerability resides in the Linux kernel's graphics processing unit memory management subsystem, specifically within the buddy allocator implementation that handles contiguous memory allocation for GPU operations. The issue manifests when the try_harder contiguous fallback mechanism attempts to satisfy memory requests but fails to maintain proper alignment boundaries. When the system encounters a memory candidate whose starting address does not align with the requested minimum block size requirements, the original implementation would abandon the allocation attempt entirely rather than attempting to correct the misalignment.
The technical flaw stems from inadequate handling of alignment constraints during memory allocation operations within the GPU memory management path. The buddy allocator's try_harder function is designed to provide fallback mechanisms when direct contiguous allocation fails, but it contained a critical oversight in its error handling logic. When a candidate memory range was identified that met size requirements but failed alignment validation, the system would simply bail out instead of attempting to realign the allocation to meet the requested boundaries. This behavior creates a scenario where legitimate memory requests could fail due to alignment artifacts rather than actual resource exhaustion.
The operational impact of this vulnerability extends beyond simple allocation failures, potentially affecting graphics performance and system stability in GPU-intensive workloads. When graphics drivers or applications request contiguous memory blocks for GPU operations, misaligned candidates could cause allocation failures that force fallback to less efficient memory management strategies. This situation becomes particularly problematic in embedded systems or real-time environments where consistent memory allocation behavior is critical for maintaining deterministic performance characteristics and preventing application crashes.
The fix implemented addresses the core issue by modifying the alignment handling logic to realign misaligned candidates down to the minimum block size boundary rather than abandoning the allocation request. This approach ensures that when a candidate memory range is identified but doesn't meet alignment requirements, the system will free the misaligned run and attempt to reallocate exactly the requested size at the next lower boundary that satisfies the minimum block size constraints. This change maintains the original requested size while ensuring proper alignment, preventing unnecessary allocation failures and maintaining system stability.
From a cybersecurity perspective, this vulnerability could potentially be exploited by malicious actors to cause denial of service conditions in systems relying heavily on GPU memory management. The improper handling of alignment constraints creates predictable failure points that could be leveraged in resource exhaustion attacks targeting graphics subsystems. The fix aligns with security best practices by ensuring proper error handling and resource management within kernel memory allocation paths. This vulnerability demonstrates the importance of careful attention to alignment requirements in kernel-level memory management, particularly in systems where multiple subsystems interact through shared memory interfaces.
The resolution approach follows established principles for secure memory management and addresses a class of issues commonly classified under CWE-129 Input Validation and CWE-787 Out-of-bounds Write. The implementation aligns with ATT&CK techniques related to privilege escalation through kernel vulnerabilities and system stability manipulation. By ensuring proper alignment handling, the fix prevents potential exploitation vectors while maintaining backward compatibility with existing graphics drivers and applications that depend on contiguous memory allocation for GPU operations. This type of vulnerability is particularly relevant in enterprise environments where GPU acceleration is commonly used for high-performance computing tasks and graphics rendering workloads.
The mitigation strategy focuses on ensuring that all memory allocation requests maintain proper alignment boundaries throughout the system's kernel memory management subsystem. The fix prevents unnecessary allocation failures while preserving the intended behavior of the buddy allocator, thereby maintaining consistent performance characteristics for GPU-intensive applications. This approach eliminates a potential attack surface where misaligned memory requests could be used to cause system instability or denial of service conditions in graphics processing environments.