CVE-2026-64524

Description

In the Linux kernel, the following vulnerability has been resolved: drm/hyperv: validate resolution_count and fix WIN8 fallback A SYNTHVID_RESOLUTION_RESPONSE with resolution_count > 64 walks past the supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT] array in the parse loop. Bound resolution_count against the array size, folded into the existing zero-check. When the WIN10 resolution probe fails, the caller in hyperv_connect_vsp() left hv->screen_*_max / preferred_* unpopulated, which sets mode_config.max_width / max_height to 0 and makes drm_internal_framebuffer_create() reject every userspace framebuffer with -EINVAL. The pre-WIN10 branch had the same gap for preferred_width / preferred_height. Use a single post-probe fallback guarded by screen_width_max == 0 so both paths converge on the WIN8 defaults.

References

• https://git.kernel.org/stable/c/13d33b9ef67066c77c84273fac5a1d3fde3533d1
• https://git.kernel.org/stable/c/1fb565b77b8f44afabb02de6310065f109d89e94
• https://git.kernel.org/stable/c/8a114b25b5521eae451b13bce98ae978624962e5
• https://git.kernel.org/stable/c/96f7de3172d4aa878b7f87173b2b3507c350fcd6
• https://git.kernel.org/stable/c/9c698b2c43c2667c34f5336bf46ad5786216ac2a