SB20260406103 - Use-after-free in Linux kernel hv driver

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-23432)

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 use-after-free in mshv_map_user_memory() error path when handling userspace memory unmapping after a failed user memory mapping operation. A local user can trigger the error path and later unmap the memory to cause a denial of service.

The issue occurs because the MMU notifier remains registered after the region is freed, and a later notifier callback accesses freed memory, potentially causing a kernel panic.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/34861bdc0c0196b6c2dd48f7454029407704ff6e
• https://git.kernel.org/stable/c/6922db250422a0dfee34de322f86b7a73d713d33