CVE-2025-39679 in Linux
Summary
by MITRE • 09/05/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau/nvif: Fix potential memory leak in nvif_vmm_ctor().
When the nvif_vmm_type is invalid, we will return error directly without freeing the args in nvif_vmm_ctor(), which leading a memory leak. Fix it by setting the ret -EINVAL and goto done.
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Analysis
by VulDB Data Team • 02/09/2026
The vulnerability identified as CVE-2025-39679 resides within the Linux kernel's graphics subsystem, specifically affecting the nouveau driver's nvif component. This issue demonstrates a classic memory management flaw that occurs during the construction of virtual memory management structures. The nouveau driver, which provides open-source support for nvidia graphics hardware, utilizes the nvif (Nouveau Interface) framework for communication between user space and kernel space components. When processing virtual memory management constructor operations, the system fails to properly handle error conditions, creating a scenario where allocated memory resources are not released back to the system.
The technical flaw manifests in the nvif_vmm_ctor() function where validation of the nvif_vmm_type parameter occurs. When an invalid type is detected, the function should immediately return an error code and clean up all allocated resources before exiting. However, the current implementation bypasses the proper cleanup mechanism, leaving memory allocations in an inconsistent state. This memory leak occurs because the args structure containing the allocated memory is not freed when the error condition is encountered, resulting in a gradual consumption of system resources that can eventually impact system stability and performance. The vulnerability specifically addresses the absence of proper resource cleanup in error paths, which represents a fundamental flaw in defensive programming practices.
The operational impact of this vulnerability extends beyond simple memory consumption issues. While the immediate effect may appear as a resource leak that accumulates over time, the long-term consequences can include degraded system performance, potential denial of service conditions, and increased memory pressure that affects other system components. The vulnerability affects systems running the Linux kernel with nouveau graphics drivers, particularly those utilizing virtual memory management features. Attackers could potentially exploit this memory leak to exhaust system resources through repeated operations that trigger the error path, though direct exploitation for privilege escalation or remote code execution appears unlikely given the nature of the flaw. The vulnerability represents a reliability issue rather than a security vulnerability, but it can contribute to system instability and may be leveraged in combination with other weaknesses to create more severe impacts.
Mitigation strategies for CVE-2025-39679 primarily involve applying the kernel patch that implements proper error handling and resource cleanup in the nvif_vmm_ctor() function. The fix ensures that when an invalid nvif_vmm_type is detected, the function sets the return value to -EINVAL and jumps to the cleanup label to release all allocated resources before returning. This approach aligns with the principle of defensive programming and follows the established pattern of resource management in kernel code. System administrators should prioritize applying the patched kernel version as soon as possible, particularly in environments where graphics-intensive operations are common or where system stability is critical. Monitoring system memory usage patterns can help identify when the memory leak is occurring, though the patch itself provides the definitive solution. The fix also demonstrates adherence to CWE-459 standards for incomplete cleanup, which specifically addresses the issue of resources not being properly released in error conditions. Additionally, this vulnerability highlights the importance of proper error handling in kernel space operations, which aligns with ATT&CK technique T1070.004 for indicator removal through deletion of system logs and memory cleanup. Organizations should ensure their kernel update processes include verification of graphics driver components, as the nouveau driver represents a common target for memory management issues in Linux systems.