CVE-2026-64524

drm/hyperv: validate resolution_count and fix WIN8 fallback

State: Published
Severity: 7.7 High
Published: Jul 25, 2026
Updated: Oct 19, 2026
Reserved: Jul 19, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.7 High	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H	Linux

Weaknesses

CWE-122 Heap-based Buffer Overflow

Affected Products

Product	Versions
LinuxLinux	76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 96f7de3172d4aa878b7f87173b2b3507c350fcd6Affected 76c56a5affeba1e163b66b9d8cc192e6154466f0 to before bc573752f3dac0d1ab8df7078c1851bc76717653Affected 76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 1fb565b77b8f44afabb02de6310065f109d89e94Affected 76c56a5affeba1e163b66b9d8cc192e6154466f0 to before a321c908f2eeea01539668eb270d074d9b88e490Affected 76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 9c698b2c43c2667c34f5336bf46ad5786216ac2aAffected 76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 8a114b25b5521eae451b13bce98ae978624962e5Affected 76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 13d33b9ef67066c77c84273fac5a1d3fde3533d1Affected
LinuxLinux	5.14Affected before 5.14Not affected 5.15.210 through 5.15.Not affected 6.1.176 through 6.1.Not affected 6.6.143 through 6.6.Not affected 6.12.93 through 6.12.Not affected 6.18.35 through 6.18.Not affected 7.0.12 through 7.0.Not affected 7.1 and laterNot affected

Product

Versions

LinuxLinux

76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 96f7de3172d4aa878b7f87173b2b3507c350fcd6Affected
76c56a5affeba1e163b66b9d8cc192e6154466f0 to before bc573752f3dac0d1ab8df7078c1851bc76717653Affected
76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 1fb565b77b8f44afabb02de6310065f109d89e94Affected
76c56a5affeba1e163b66b9d8cc192e6154466f0 to before a321c908f2eeea01539668eb270d074d9b88e490Affected
76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 9c698b2c43c2667c34f5336bf46ad5786216ac2aAffected
76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 8a114b25b5521eae451b13bce98ae978624962e5Affected
76c56a5affeba1e163b66b9d8cc192e6154466f0 to before 13d33b9ef67066c77c84273fac5a1d3fde3533d1Affected

LinuxLinux

5.14Affected
before 5.14Not affected
5.15.210 through 5.15.*Not affected
6.1.176 through 6.1.*Not affected
6.6.143 through 6.6.*Not affected
6.12.93 through 6.12.*Not affected
6.18.35 through 6.18.*Not affected
7.0.12 through 7.0.*Not affected
7.1 and laterNot affected

References

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