The rivafb driver in the Linux kernel calculates FIFO arbitration parameters using the mclk_khz value derived from a PCI device’s PLL. The code divides by this value without checking if it is zero, so a device that reports a zero mclk_khz can trigger a divide error. The error causes the kernel to panic, leading to a system reboot or service interruption. This results in a denial of service by crashing the kernel.

The flaw exists in the Linux kernel’s rivafb driver, which is used on systems that support RIVA NV3 graphics hardware. All kernels that include this driver and have not yet applied the patch that adds a zero‑division check are affected. No specific kernel versions are listed, so any build containing the vulnerable code may be impacted until the update is installed.

The EPSS score is below 1% and the vulnerability is not listed in the CISA KEV catalog, indicating limited current exploitation activity. Exploitation requires a program that can issue the FBIOPUT_VSCREENINFO ioctl on a /dev/fb* device and a device capable of exposing a zero mclk_khz value, such as a crafted or emulated PCI device. Once the ioctl is invoked, the divide error triggers a kernel panic. The exploit would need privileged access to the graphics device and a malicious hardware configuration, thereby limiting the attack surface.