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VulnerabilityPublished Updated

CVE-2026-64524: Linux kernel · drm/hyperv: validate resolution_count and fix WIN8 fallback

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.7 High · fixed in bc573752f3dac0d1ab8df7078c1851bc76717653 : patch Linux kernel soon.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
7.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in bc573752f3dac0d1ab8df7078c1851bc76717653, a321c908f2eeea01539668eb270d074d9b88e490, 96f7de3172d4aa878b7f87173b2b3507c350fcd6 +4
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 76c56a5affeba1e163b66b9d8cc192e6154466f0, < bc573752f3dac0d1ab8df7078c1851bc76717653
Fixed in
  • bc573752f3dac0d1ab8df7078c1851bc76717653
LinuxLinuxAffected
  • ≥ 76c56a5affeba1e163b66b9d8cc192e6154466f0, < a321c908f2eeea01539668eb270d074d9b88e490
Fixed in
  • a321c908f2eeea01539668eb270d074d9b88e490
LinuxLinuxAffected
  • ≥ 76c56a5affeba1e163b66b9d8cc192e6154466f0, < 96f7de3172d4aa878b7f87173b2b3507c350fcd6
Fixed in
  • 96f7de3172d4aa878b7f87173b2b3507c350fcd6
LinuxLinuxAffected
  • ≥ 76c56a5affeba1e163b66b9d8cc192e6154466f0, < 13d33b9ef67066c77c84273fac5a1d3fde3533d1
Fixed in
  • 13d33b9ef67066c77c84273fac5a1d3fde3533d1
LinuxLinuxAffected
  • ≥ 76c56a5affeba1e163b66b9d8cc192e6154466f0, < 9c698b2c43c2667c34f5336bf46ad5786216ac2a
Fixed in
  • 9c698b2c43c2667c34f5336bf46ad5786216ac2a
LinuxLinuxAffected
  • ≥ 76c56a5affeba1e163b66b9d8cc192e6154466f0, < 8a114b25b5521eae451b13bce98ae978624962e5
Fixed in
  • 8a114b25b5521eae451b13bce98ae978624962e5

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

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