Improper access control in Linux kernel - CVE-2026-80724

Vulnerability identifier: #VU146058

CSH Severity: Low

CVSS v4: 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]

CVE-ID: CVE-2026-80724

CWE-ID: CWE-284

Exploitation vector: Local access

Exploit availability: Public exploit is available

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.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17

• Exploit #12989 - cve-writeups-and-pocs (CVE-2026-80724 PoC + full write-up — Linux kernel ptp/vmclock read-only mapping becomes writable (VM_MAYWRITE). Discovered, reported & fixed by Abdifatah Suruur (suruurism)) (August 31, 2026)

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

• Improper access control in Linux kernel ptp driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more