CVE-2023-53002 in Linux
Summary
by MITRE • 03/27/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/i915: Fix a memory leak with reused mmap_offset
drm_vma_node_allow() and drm_vma_node_revoke() should be called in balanced pairs. We call drm_vma_node_allow() once per-file everytime a user calls mmap_offset, but only call drm_vma_node_revoke once per-file on each mmap_offset. As the mmap_offset is reused by the client, the per-file vm_count may remain non-zero and the rbtree leaked.
Call drm_vma_node_allow_once() instead to prevent that memory leak.
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Analysis
by VulDB Data Team • 12/07/2025
The vulnerability identified as CVE-2023-53002 resides within the Linux kernel's graphics subsystem, specifically affecting the intel i915 driver through the direct rendering manager framework. This memory leak occurs in the handling of memory mapping operations for graphics resources, where the kernel fails to properly manage reference counting for virtual memory areas. The issue manifests when clients reuse mmap_offset values, creating a scenario where memory allocated for virtual memory management structures becomes permanently leaked due to improper cleanup operations.
The technical flaw stems from an imbalance in the calling pattern of DRM virtual memory management functions. The drm_vma_node_allow() function is invoked once per file every time a user calls mmap_offset, while drm_vma_node_revoke() is only called once per file for each mmap_offset. This asymmetry becomes problematic when the same mmap_offset is reused by clients, as the per-file vm_count counter remains non-zero and prevents proper cleanup of the red-black tree data structures that manage virtual memory mappings. This violation of balanced function calls creates a memory leak that accumulates over time as applications make repeated mmap_offset requests.
The operational impact of this vulnerability extends beyond simple memory consumption, as it can lead to progressive system degradation and potential denial of service conditions in graphics-intensive applications. When applications repeatedly request memory mappings and reuse the same offset values, the kernel's virtual memory management subsystem gradually consumes additional memory that cannot be reclaimed. This is particularly concerning in server environments or systems running graphics-intensive workloads where memory resources are already constrained, as the leak can eventually consume significant portions of available system memory.
The resolution for this vulnerability involves replacing the current calling pattern with drm_vma_node_allow_once(), which ensures that the allow operation is performed only once per virtual memory node regardless of how many times the mmap_offset is reused. This change aligns with the fundamental principle of balanced resource management where every allocation must have a corresponding deallocation, preventing the accumulation of unreleased memory structures. This fix directly addresses the root cause identified in the vulnerability description and prevents the memory leak from occurring during normal operation of graphics applications.
From a cybersecurity perspective, this vulnerability represents a classic case of resource management error that could be exploited to cause system instability or denial of service conditions. The memory leak could potentially be amplified through repeated operations, making it a target for resource exhaustion attacks. The vulnerability aligns with CWE-401: Improper Release of Memory and follows patterns commonly seen in kernel memory management flaws that can be exploited to consume system resources. This type of vulnerability is particularly relevant in the context of the ATT&CK framework's resource exhaustion tactics, where adversaries may attempt to degrade system performance through memory consumption attacks.
The fix demonstrates proper adherence to kernel development practices and resource management principles, ensuring that virtual memory management structures are correctly maintained throughout the lifecycle of graphics memory mappings. This vulnerability highlights the importance of careful reference counting and balanced function calls in kernel subsystems, particularly those handling memory mapping operations. The solution emphasizes the need for comprehensive testing of resource management scenarios, including reuse patterns and long-running applications, to prevent similar issues from manifesting in production environments.