Out-of-bounds read in Linux kernel - CVE-2026-64527

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Main Vulnerability Database Vulnerabilities #VU139405

Out-of-bounds read in Linux kernel - CVE-2026-64527

Published: July 27, 2026


Vulnerability identifier: #VU139405
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64527
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in hyperv_receive() and hyperv_receive_sub() in the Hyper-V DRM protocol handler when handling oversized or malformed VMBus packets. A remote attacker can send a specially crafted VMBus packet to cause a denial of service.

An error path may report a required packet length larger than the 16 KiB receive buffer, leading the code to use that length unsafely if forwarded for copying.


Affected software

Linux kernel
Ubuntu
linux-aws (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-64527

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins