Bug 2507029 (CVE-2026-64524) - CVE-2026-64524 kernel: drm/hyperv: validate resolution_count and fix WIN8 fallback
Summary: CVE-2026-64524 kernel: drm/hyperv: validate resolution_count and fix WIN8 fal...
Keywords:
Status: NEW
Alias: CVE-2026-64524
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-25 10:01 UTC by OSIDB Bzimport
Modified: 2026-07-28 15:34 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-07-25 10:01:19 UTC
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.

Comment 1 Mauro Matteo Cascella 2026-07-28 15:32:43 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072533-CVE-2026-64524-0002@gregkh/T


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