SB2026102233 - Use-after-free in Linux kernel sched ext

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-98463)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 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]

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().

Remediation

Install update from vendor's website.

References

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