CVE-2026-64527

Guest-memory disclosure via unchecked VMBus lengths

Published Jul 25, 2026 · Updated Jul 25, 2026

Information disclosure in the Linux Kernel Hyper-V DRM driver allows attackers to expose stale guest memory through malformed VMBus packets. hyperv_receive_sub() dispatches on an unchecked message type and copies the entire 16 KiB receive buffer instead of the bytes actually received. Reachability requires a Linux guest using the Hyper-V synthetic video device and a malicious or compromised host that can supply truncated or oversized VMBus responses.

CVSS severity4.0
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in the Linux Kernel Hyper-V DRM driver allows attackers to expose stale guest memory through malformed VMBus packets. hyperv_receive_sub() dispatches on an unchecked message type and copies the entire 16 KiB receive buffer instead of the bytes actually received. Reachability requires a Linux guest using the Hyper-V synthetic video device and a malicious or compromised host that can supply truncated or oversized VMBus responses.

The record

CVE
CVE-2026-64527
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.14
  2. Affected versionversion=76c56a5affeba1e163b66b9d8cc192e6154466f0 <049a6b474823049fe60212f25f26e4b30f44ee8f
  3. Affected versionversion=76c56a5affeba1e163b66b9d8cc192e6154466f0 <164dc7bf17609340233c6bf4f66bb7c7008a0511
  4. Affected versionversion=76c56a5affeba1e163b66b9d8cc192e6154466f0 <57d5d697642e05d5dd2d40660817765943dd709f
  5. Affected versionversion=76c56a5affeba1e163b66b9d8cc192e6154466f0 <588c84b461393ff1998ac7b97b04f953f642e0df
  6. Affected versionversion=76c56a5affeba1e163b66b9d8cc192e6154466f0 <7f87763f47a3c22fb50265a00619ef10f2394b18
  7. Affected versionversion=76c56a5affeba1e163b66b9d8cc192e6154466f0 <c8974d96b6a5496f33dc69a3ce28a7bf5078def4
  8. Affected versionversion=76c56a5affeba1e163b66b9d8cc192e6154466f0 <f5251226551bfec98c4705641b6f94ff1f238d91

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.14; version=76c56a5affeba1e163b66b9d8cc192e6154466f0 <049a6b474823049fe60212f25f26e4b30f44ee8f; version=76c56a5affeba1e163b66b9d8cc192e6154466f0 <164dc7bf17609340233c6bf4f66bb7c7008a0511; version=76c56a5affeba1e163b66b9d8cc192e6154466f0 <57d5d697642e05d5dd2d40660817765943dd709f; version=76c56a5affeba1e163b66b9d8cc192e6154466f0 <588c84b461393ff1998ac7b97b04f953f642e0df; version=76c56a5affeba1e163b66b9d8cc192e6154466f0 <7f87763f47a3c22fb50265a00619ef10f2394b18; version=76c56a5affeba1e163b66b9d8cc192e6154466f0 <c8974d96b6a5496f33dc69a3ce28a7bf5078def4; version=76c56a5affeba1e163b66b9d8cc192e6154466f0 <f5251226551bfec98c4705641b6f94ff1f238d91

Published CVSS scores

4.0Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

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