CVE-2026-90245: Undefined Security Weakness

In the Linux kernel, the following vulnerability has been resolved:

fbdev: kyro: Validate overlay viewport coordinates

The overlay viewport end coordinates are computed from the viewport origin and dimensions using 32-bit unsigned arithmetic. Large input values can cause these calculations to wrap around before the resulting coordinates are passed to SetOverlayViewPort().

SetOverlayViewPort() packs the viewport coordinates into 16-bit register fields. The X coordinates are additionally adjusted by +2 and +1 before being written. Validate the coordinate calculations for 32-bit wraparound and ensure that the adjusted coordinates fit within their 16-bit register fields before calling SetOverlayViewPort().

Found by Linux Verification Center (linuxtesting.org) with SVACE.