Reachable assertion in Linux kernel - CVE-2026-98923

Vulnerability identifier: #VU157592

CSH Severity: Low

CVSS v4: 0 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98923

CWE-ID: CWE-617

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to trigger a spurious kernel warning.

The vulnerability exists due to a reachable warning assertion in the arm64 ioremap_prot() function when processing valid user mappings whose protection values lack PTE_USER. A local privileged user can map a stack-top page through /dev/mem with PROT_NONE and then read that process's cmdline entry in /proc to trigger WARN_ON_ONCE() through generic_access_phys().

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/0b04af3d88bb7fc69b2d92457890608860e42365
• https://git.kernel.org/stable/c/9b583795feb51f8d50203228d001760d1344ef01
• https://git.kernel.org/stable/c/b17aa4955e3a694c663ebe99626e4c76ca4f7cfb
• https://git.kernel.org/stable/c/bb756b11ad63832ebee58caf9e8f9381eaecff9f
• https://git.kernel.org/stable/c/fddc90d4af4550af410f52d11bbf6b5f36443838

• Reachable assertion in Linux kernel include asm
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more