How to Fix CVE-2026-23433: Linux (Bundle Sibling)

*By Sai Kiran Pandrala*

Last verified: 2026-05-25

CVE-2026-23433 is a sibling vulnerability in the same Linux Linux advisory bundle as CVE-2026-23401. The same patched build closes every CVE in the bundle, so the remediation procedure for CVE-2026-23433 matches the primary write-up.

What is different about CVE-2026-23433?

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 re...

Impact is consistent with the bundle: compromise of the affected component as described in the vendor advisory. The patched build closes every code path in the advisory in one update.

How to fix CVE-2026-23433

Apply the patched build per the primary write-up: How to Fix CVE-2026-23401.

For a quick check, confirm the running version of Linux:

# Confirm the installed version via your package manager
dpkg -l | grep -i linux   # Debian/Ubuntu
rpm -qa | grep -i linux   # RHEL/CentOS/Rocky

Frequently asked questions

Is CVE-2026-23433 being actively exploited?

Not at the time of writing. It is not listed in CISA's Known Exploited Vulnerabilities catalog. That status can change, so monitor the vendor advisory and the KEV catalog if the system is exposed.

How severe is CVE-2026-23433?

CVSS has not been published in the data sources used for this page. Refer to the vendor advisory and NVD for any score updates.

Do I have to take Linux offline to apply the patch?

It depends on the deployment. High-availability or clustered installs can usually patch one node at a time with no full outage. Standalone installs typically need a short restart. Always follow the vendor's documented upgrade steps.

What if my vulnerability scanner still flags CVE-2026-23433 after I patch?

Re-run the scan after a service restart, then confirm the scanner's plugin set is up to date. Some scanners detect by banner version only and lag the official fix metadata by a release.

References

• Official vendor advisory: https://git.kernel.org/stable/c/ac3e12bc195786d3d44d730b5b2259fd36191848
• NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-23433
• CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Primary write-up: How to Fix CVE-2026-23401

*Written by Sai Kiran Pandrala. Last verified 2026-05-25. Part of the Linux Linux advisory bundle. Full procedure at how-to-fix-cve-2026-23401.*