Infinite loop in Linux kernel - CVE-2026-89991

Vulnerability identifier: #VU150292

CSH Severity: Low

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

CVE-ID: CVE-2026-89991

CWE-ID: CWE-835

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 an infinite loop in __pcpu_freelist_push() when an NMI re-enters pcpu_freelist_push() while the interrupted context holds the only possible CPU's freelist lock. A local user can trigger the affected BPF freelist push path to cause a denial of service.

The issue occurs on systems with only one possible CPU.

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

• https://git.kernel.org/stable/c/a24a146ae2cb5d9faeea96d10010fcb6579abe1f
• https://git.kernel.org/stable/c/a5b5e62baceff9e252c6535cf42a027d04f226cf
• https://git.kernel.org/stable/c/efebf6496685c93150df5bb0794363ae70c5f58a

• Infinite loop in Linux kernel bpf
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more