Linux Kernel Hyperv DRM: Unbounded Array Index & Framebuffer Init Failure
CVE-2026-64524 Published on July 25, 2026
drm/hyperv: validate resolution_count and fix WIN8 fallback
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.
Products Associated with CVE-2026-64524
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Affected Versions
Linux:- Version 76c56a5affeba1e163b66b9d8cc192e6154466f0 and below 96f7de3172d4aa878b7f87173b2b3507c350fcd6 is affected.
- Version 76c56a5affeba1e163b66b9d8cc192e6154466f0 and below bc573752f3dac0d1ab8df7078c1851bc76717653 is affected.
- Version 76c56a5affeba1e163b66b9d8cc192e6154466f0 and below 1fb565b77b8f44afabb02de6310065f109d89e94 is affected.
- Version 76c56a5affeba1e163b66b9d8cc192e6154466f0 and below a321c908f2eeea01539668eb270d074d9b88e490 is affected.
- Version 76c56a5affeba1e163b66b9d8cc192e6154466f0 and below 9c698b2c43c2667c34f5336bf46ad5786216ac2a is affected.
- Version 76c56a5affeba1e163b66b9d8cc192e6154466f0 and below 8a114b25b5521eae451b13bce98ae978624962e5 is affected.
- Version 76c56a5affeba1e163b66b9d8cc192e6154466f0 and below 13d33b9ef67066c77c84273fac5a1d3fde3533d1 is affected.
- Version 5.14 is affected.
- Before 5.14 is unaffected.
- Version 5.15.210, <= 5.15.* is unaffected.
- Version 6.1.176, <= 6.1.* is unaffected.
- Version 6.6.143, <= 6.6.* is unaffected.
- Version 6.12.93, <= 6.12.* is unaffected.
- Version 6.18.35, <= 6.18.* is unaffected.
- Version 7.0.12, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.