CVE-2026-23433
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk1th percentile - higher than 1% of all known CVEs
Summary
In the Linux kernel arm_mpam driver, a null pointer dereference occurs when restoring memory bandwidth counters. When an MSC is brought offline and online, mpam_restore_mbwu_state() does not set mbwu_arg.val, causing a kernel oops.
Risk Assessment
An attacker could trigger a kernel oops by cycling an MSC offline/online, leading to denial of service.
Recommendation
Apply the kernel patch that provides a local variable for val to avoid null pointer dereference. Update the kernel.
Original NVD description (English source)
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.