NULL pointer dereference in Linux kernel - CVE-2026-89958

Vulnerability identifier: #VU150324

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-2026-89958

CWE-ID: CWE-476

Exploitation vector: Local access

Exploit availability: No public exploit available

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

The vulnerability exists due to a null pointer dereference in the s390/vfio-ap AP bus configuration callbacks when handling AP bus configuration changes while matrix_mdev->kvm is unset. A local user can trigger the AP bus configuration callbacks to cause a denial of service.

Linux kernel
Debian Linux
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)
linux (Debian 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
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/178ea7a1c2c3c0c01d14b8f60aa35f1e0cdc6b78
• https://git.kernel.org/stable/c/334b435b951353f934d5110c4630e0cb58d2f9a7
• https://git.kernel.org/stable/c/4f7e869d0db24ae07b4c888fd3bc21554eef775d
• https://git.kernel.org/stable/c/5e932abfcce6189d067fffb0eb8214443bc04374
• https://git.kernel.org/stable/c/d50346801b4f144e42b49cd4f1496010498ab114

• NULL pointer dereference in Linux kernel s390 crypto driver
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more