How to Fix CVE-2026-23427: Linux (Bundle Sibling)

*By Sai Kiran Pandrala*

Last verified: 2026-05-25

CVE-2026-23427 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-2026-23427 matches the primary write-up.

What is different about CVE-2026-23427?

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

ksmbd: fix use-after-free in durable v2 replay of active file handles

parse_durable_handle_context() unconditionally assigns dh_info->fp->conn

to the current connection when handling a DURABLE_REQ_V2 context with

SMB2_FLAGS_REPLAY_OPERATION. ksmbd_lookup_fd_cguid() does not filter by

fp->conn, so it returns file handles that are already actively connected. The unconditional overwrite replaces fp->conn, and when the overwrit...

Impact is consistent with the bundle: use-after-free that can lead to heap corruption and code execution. The patched build closes every code path in the advisory in one update.

How to fix CVE-2026-23427

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-2026-23427 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-2026-23427?

CVSS rates it 9.8 (Critical). Use that score to set your patch priority alongside the other items in your queue.

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-2026-23427 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/b0158d9d6f4ec5941e49a0b812735db2844f9975
• NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-23427
• 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.*