CVE-2026-43202

Vulnerability

Overview

In the Linux kernel's framebuffer subsystem, the vt8500lcdfb driver allocates a coherent DMA buffer for fbi->fb.screen_buffer via dma_alloc_coherent() but does not free it when an error is encountered during initialization. This oversight results in a memory leak that persists until the system is rebooted [1][2][3][4].

Exploitation

An attacker with the ability to load or trigger the vt8500lcdfb driver (e.g., by inserting the module or causing an error during boot) can repeatedly invoke the leaking code path. No special privileges are required beyond local access to the affected kernel module. The error path is typically reached when hardware initialization fails, making this a locally exploitable condition.

Impact

The vulnerability leads to a gradual exhaustion of DMA-coherent memory, which can degrade system performance and ultimately cause a denial of service (DoS) if critical allocations fail. The CVSS v3 severity is 5.5 (Medium), reflecting the local attack vector and the availability impact.

Mitigation

The Linux kernel stable tree has released patches that add the missing dma_free_coherent() call in the error path [1][2][3][4]. Users should apply these patches or update to a kernel version where the fix is included.