SB20260816345 - Improper access control in Linux kernel mm

Description

This security bulletin contains information about 1 vulnerability.

1) Improper access control (CVE-ID: CVE-2026-72180)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a local user to bypass a userfaultfd write-protection trap.

The vulnerability exists due to improper preservation of protection metadata in change_non_present_huge_pmd() when processing a writable device-private PMD swap entry during a huge PMD downgrade. A local user can invoke mprotect() on a UFFD_WP-marked device-private THP to bypass a userfaultfd write-protection trap.

The issue occurs because the uffd write-protect bit is stripped and the trap is bypassed on swap-in.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/2611f7521c6c124b1bef1be4fc319e0ca144502f
• https://git.kernel.org/stable/c/f7e2c21bd1f57cd5350eecdfdb5d6025ca6afbab