CVE-2026-90245: fbdev: kyro: Validate overlay viewport coordinates
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.
Affected Software
Event History
Frequently Asked Questions
What input is required to trigger the issue?
The overlay viewport origin and dimension values must be large enough to cause 32-bit unsigned arithmetic to wrap when calculating the viewport end coordinates. The resulting X-coordinate adjustments must also exceed what can be represented in the 16-bit register fields.
What can be done before the fix is deployed?
Avoid supplying overlay viewport coordinates or dimensions that could overflow 32-bit coordinate calculations or produce adjusted X coordinates outside the 16-bit register range. Restrict access to interfaces that allow callers to control overlay viewport settings where possible.