Improper locking in Linux kernel - CVE-2026-98930

Vulnerability identifier: #VU157584

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98930

CWE-ID: CWE-667

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to potentially cause a denial of service.

The vulnerability exists due to improper locking in the Linux kernel's s390 KVM interrupt handling when processing a SIGP Stop and Store Status operation for an already stopped vCPU. A local user can trigger a status-store operation that writes to userspace while a spinlock is held, allowing a page fault to require blocking in an atomic context and potentially cause 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/3bd77c59576b1d447fd56cc689ae9523a334b924
• https://git.kernel.org/stable/c/a379ac504fcb8c6fc2aa36203f5489b9581eb2e0
• https://git.kernel.org/stable/c/d0e3bf633f0585a0c2c2105ea7723777d764fae5
• https://git.kernel.org/stable/c/d343407b728a80b74be3c24b59f15e60289ea527

• Improper locking in Linux kernel s390 kvm
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more