CVE-2026-23433

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

arm_mpam: Fix null pointer dereference when restoring bandwidth counters

When an MSC supporting memory bandwidth monitoring is brought offline and

then online, mpam_restore_mbwu_state() calls __ris_msmon_read() via ipi to

restore the configuration of the bandwidth counters. It doesn't care about

the value read, mbwu_arg.val, and doesn't set it leading to a null pointer

dereference when __ris_msmon_read() adds to it. This results in a kernel

oops with a call trace such as:

Call trace:

__ris_msmon_read+0x19c/0x64c (P)

mpam_restore_mbwu_state+0xa0/0xe8

smp_call_on_cpu_callback+0x1c/0x38

process_one_work+0x154/0x4b4

worker_thread+0x188/0x310

kthread+0x11c/0x130

ret_from_fork+0x10/0x20

Provide a local variable for val to avoid __ris_msmon_read() dereferencing

a null pointer when adding to val.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References