Out-of-bounds write in Linux kernel - CVE-2026-98918

Vulnerability identifier: #VU157587

CSH Severity: Low

CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98918

CWE-ID: CWE-787

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to corrupt kernel memory and cause a denial of service.

The vulnerability exists due to an out-of-bounds write in the Linux kernel's damon_ptep_mkold() function when an unaligned sampling address is passed to arm64 page-table access-flag clearing helpers. A local privileged user can trigger affected DAMON sampling to cause the page-table walk to clear access flags beyond the sampled block and potentially beyond the page-table page, corrupting adjacent kernel memory and causing a denial of service.

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 kernel - update to 7.0 rc3
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

• https://git.kernel.org/stable/c/d5208de0799c506d3315b6f96d034c38e4509dbb
• https://git.kernel.org/stable/c/f166586f74dd5d9cbadaabf86ef81c8ddf6cafa7

• Out-of-bounds write in Linux kernel damon
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more