Use-after-free in Linux kernel - CVE-2026-98463

Vulnerability identifier: #VU156761

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-2026-98463

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to potentially cause a denial of service through access to freed kernel memory.

The vulnerability exists due to a use-after-free in the Linux kernel sched_ext scheduler when remote task activation incorrectly sets SCX_RQ_IN_WAKEUP and leaves a deferred reenqueue request pending. A local user can trigger the affected scheduling sequence to leave a request referencing freed per-CPU scheduler memory after the scheduler is disabled, potentially causing a kernel crash when the next scheduler dereferences it in run_deferred().

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/3fdf2ceb31e8aff77451e468bc8409e10587916a
• https://git.kernel.org/stable/c/6c401ae426e20e53a3398a8e79afd0964c0f5110
• https://git.kernel.org/stable/c/df5cdc2c832ca4e8a6d774596b9005558761a403

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