Use-after-free in Linux kernel - CVE-2026-89928

Vulnerability identifier: #VU150351

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-89928

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to compromise confidentiality, integrity, and availability.

The vulnerability exists due to a use-after-free in the KVM x86 MMU lockless rmap walk when performing lockless rmap aging while a writer populates or frees an rmap. A local user can trigger lockless rmap aging concurrently with rmap modification to compromise confidentiality, integrity, and availability.

The issue requires CONFIG_KVM_MMU_LOCKLESS_AGING to be enabled.

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/41debfc98526c0a95c41a62435aca0a70340a26d
• https://git.kernel.org/stable/c/8edb3c09e43f7cd8a5dfd291c6e0fc9c74d4621d
• https://git.kernel.org/stable/c/e428f9779a43737d830111238816f1928b07aefb

• Use-after-free in Linux kernel kvm mmu
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more