SB2026102660 - NULL pointer dereference in Linux kernel mm

Description

This security bulletin contains information about 1 vulnerability.

1) NULL pointer dereference (CVE-ID: CVE-2026-99093)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local privileged user to cause a denial of service by triggering a kernel panic during boot.

The vulnerability exists due to a null pointer dereference in pagetable_free_kernel() when boot-time function tracing triggers deferred kernel page table freeing before workqueue initialization. A local privileged user can configure boot-time tracing with ftrace=function ftrace_filter=pud_free_pmd_page to trigger work submission through the still-null system_percpu_wq pointer and cause a kernel panic.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/2fb552b0bee70c24c092720028ab4620f5eb2646
• https://git.kernel.org/stable/c/7a25ca170c12a9328f6fcf4410713beb516b01c0
• https://git.kernel.org/stable/c/df6c704a08bc0925d5db047b0a6221f962bda4d9