CVE-2025-39679: 
Linux Debian vulnerability analysis and mitigation

A memory leak vulnerability was identified in the Linux kernel, specifically in the drm/nouveau/nvif component. The issue was discovered and published on September 5, 2025. The vulnerability occurs in the nvifvmmctor() function when handling invalid nvifvmmtype values, where the function returns an error without properly freeing allocated memory resources (NVD CVE).

The vulnerability stems from a flaw in the error handling path of the nvifvmmctor() function within the Linux kernel's DRM (Direct Rendering Manager) Nouveau driver. When an invalid nvifvmmtype is encountered, the function returns an error directly without properly freeing the allocated args memory, resulting in a memory leak. The fix involves setting the return value to -EINVAL and implementing proper cleanup through a 'goto done' statement (NVD CVE).

The vulnerability results in a memory leak in the Linux kernel's Nouveau driver, which could lead to gradual system resource depletion over time. While memory leaks are generally less severe than other vulnerability types, they can impact system stability and performance, particularly in long-running systems (NVD CVE).

The vulnerability has been resolved in the Linux kernel through a patch that properly handles memory cleanup in the error path. The fix involves modifying the nvifvmmctor() function to ensure proper resource cleanup when encountering invalid nvifvmmtype values (NVD CVE).