Use-after-free in Linux kernel - CVE-2026-98258

Vulnerability identifier: #VU153766

CSH Severity: Low

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

CVE-ID: CVE-2026-98258

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to trigger access to freed kernel timer memory.

The vulnerability exists due to use-after-free in the POSIX CPU timer subsystem when timer expiry handling races with timer modification and deletion. A local user can race timer_settime() and timer_delete() calls with expiry list traversal to trigger access to freed kernel timer memory.

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/4336e3f47d9d516441066e9a65eaf076790d8d45
• https://git.kernel.org/stable/c/9971dac1a77845ff467146915fcbb9170f6a8209
• https://git.kernel.org/stable/c/c21eaa72f02fc6e85621cbe09d303d8fb8bd39cd

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