SB2026061017 - Use-after-free in Linux kernel arm64 kvm

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-46317)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in the nested_mmus array in arm64 KVM nested virtualization when reallocating nested MMU structures while the array is being walked under mmu_lock. A local user can trigger nested vcpu initialization and concurrent MMU notifier activity to cause a denial of service.

The issue arises from a race condition between nested vcpu initialization and the MMU notifier path.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/4424dbcb06d68e34e51c019a5781a7dc00731971
• https://git.kernel.org/stable/c/70543358fa08e0f7cebc3447c3b70fe97ad7aaa8
• https://git.kernel.org/stable/c/918450ad6010df6ecd2efde12a1409e011da22d6