SB2026082839 - Improper access control in Linux kernel ptp driver

Description

This security bulletin contains information about 1 vulnerability.

1) Improper access control (CVE-ID: CVE-2026-80724)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a local user to modify host-written timekeeping data.

The vulnerability exists due to improper access control in vmclock_miscdev_mmap() when handling read-only mappings of the shared vmclock ABI page. A local user can map the page read-only and then change it to writable with mprotect() to modify host-written timekeeping data.

The corrupted data can include the sequence counter, UTC time, and TSC offset.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/2496e141827102d6af512950057d402a2cfb2bfc
• https://git.kernel.org/stable/c/2e596e7814ba38cdc129991058b6c254ed37cb11
• https://git.kernel.org/stable/c/5b4f2bec7bea6c04084d720d731bedee7caf878d