CVE-2026-64524: Linux kernel · drm/hyperv: validate resolution_count and fix WIN8 fallback
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/96f7de3172d4aa878b7f87173b2b3507c350fcd6 (opens in a new tab)
- git.kernel.org/stable/c/bc573752f3dac0d1ab8df7078c1851bc76717653 (opens in a new tab)
- git.kernel.org/stable/c/1fb565b77b8f44afabb02de6310065f109d89e94 (opens in a new tab)
- git.kernel.org/stable/c/a321c908f2eeea01539668eb270d074d9b88e490 (opens in a new tab)
- git.kernel.org/stable/c/9c698b2c43c2667c34f5336bf46ad5786216ac2a (opens in a new tab)
- git.kernel.org/stable/c/8a114b25b5521eae451b13bce98ae978624962e5 (opens in a new tab)
- git.kernel.org/stable/c/13d33b9ef67066c77c84273fac5a1d3fde3533d1 (opens in a new tab)