How to Fix CVE-2025-37924: In the Linux kernel, the following vulnerability has been resolved:

ksmbd: f... in Linux

What is CVE-2025-37924?

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

ksmbd: fix use-after-free in kerberos authentication

Setting sess->user = NULL was introduced to fix the dangling pointer

created by ksmbd_free_user. However, it is possible another thread could

be operating on the session and make use of sess->user after it has been

passed to ksmbd_free_user but before sess->user is set to NULL.

In short, a successful attacker gets use-after-free that can lead to heap corruption. No confirmed in-the-wild exploitation is listed in CISA KEV at the time of writing, but the CVSS rating still warrants prompt patching.

Am I affected?

Check whether you run Linux Linux in your environment, then compare your installed version against the Affected row above.

uname -r

How to fix CVE-2025-37924

1. Read the official vendor advisory linked at the bottom of this page and identify the exact patched build for your release train.
2. Download the patched build of Linux from the vendor's support portal. Use only signed images from the vendor.
3. Back up configuration and, where supported, take a snapshot of the host or appliance before you start.
4. Apply the update following the vendor's documented procedure. For clustered or high-availability deployments, patch the standby node first, fail over, then patch the previously active node.
5. Restart the affected service or appliance if the upgrade procedure requires it.
6. Re-run the version check from the previous section and confirm the build matches the fixed release.

Patch via your OS package manager

# Patched version is 6.1.138 (from the vendor advisory).
# Debian / Ubuntu
sudo apt update
sudo apt install --only-upgrade linux-image-generic=6.1.138

# RHEL / Rocky / AlmaLinux / Fedora
sudo dnf upgrade linux-image-generic

# openSUSE
sudo zypper update linux-image-generic

# Verify the running version matches the fixed version
dpkg -s linux-image-generic 2>/dev/null | grep -i version || rpm -q linux-image-generic 2>/dev/null

# Windows: pull the cumulative update that ships this fix.
Install-Module PSWindowsUpdate -Force -SkipPublisherCheck
Get-WindowsUpdate -AcceptAll -Install -AutoReboot

Verify the fix landed

# 1. Confirm the running version matches the fixed-in version from the advisory:
#    https://git.kernel.org/stable/c/e34a33d5d7e87399af0a138bb32f6a3e95dd83d2
#    Use the platform-specific version probe above.

# 2. Re-scan with your vulnerability scanner (Nessus, Qualys, Tenable, OpenVAS).
#    The scanner should no longer flag CVE-2025-37924 on the patched target.

# 3. Inspect recent service / kernel logs for crash loops or rollback events.
journalctl -u <service> --since "10 minutes ago"
dmesg --since "10 minutes ago"

If you can't patch immediately

No official vendor workaround is published for this CVE at the time of writing; patching is the primary remediation. If patching has to wait, restrict network access to the affected component to trusted administrative networks and monitor logs for indicators of compromise listed in the advisory.

How to verify the fix worked

Confirm the running build of Linux matches the fixed version listed by the vendor. Re-run any vulnerability scanner you used previously and confirm the finding for CVE-2025-37924 has cleared. Where the vendor publishes a detection rule or IOCs, sweep your logs for evidence of pre-patch exploitation.

Why this CVE matters

CVSS 9.8 (Critical) reflects either remote, unauthenticated exploitability, full impact on confidentiality / integrity / availability, or both. Most internal SLAs map a Critical rating to a 7-to-15 day patch deadline regardless of in-the-wild reports. Public-facing instances should be patched on the shorter end of that window.

Monitoring and detection

After you apply the patch, treat the affected component as a known-good baseline and watch for regression. Concrete steps:

• Re-run your usual vulnerability scanner on a weekly cycle for the next month and confirm the finding stays clear.
• Forward the affected component's logs to your SIEM, then write a rule for any failed-auth burst or unusual configuration change on the component.
• If the vendor advisory lists indicators of compromise, hash patterns, or specific log strings, build detection rules in your SIEM around them and back-search the last 90 days of logs.
• Tag the patched build in your CMDB so future audits can confirm it stayed patched through any rebuild or re-image.

Defensive hardening beyond the patch

Patching closes this specific CVE. A few common-sense controls reduce the blast radius of the next one in the same component:

• Restrict network access to the affected component to known administrative networks at the firewall.
• Enable verbose audit logging and forward events to your SIEM for at least 90 days.
• Enforce two-factor authentication on any account that can administer the affected component.
• Run a fresh asset inventory after the patch to confirm no shadow instances were missed.

Frequently asked questions

Related fixes

Other vulnerabilities in the same area that are worth patching alongside this one:

• How to Fix CVE-2025-39946: Linux (Bundle Sibling) — Linux (Bundle Sibling)
• How to Fix CVE-2025-68263: Linux (Bundle Sibling) — Linux (Bundle Sibling)
• How to Fix CVE-2025-38352: Security Vulnerability in Linux Linux , Security Vulnerability in Linux Linux

Is CVE-2025-37924 being actively exploited?

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

How severe is CVE-2025-37924?

CVSS rates it 9.8 (Critical). Treat it accordingly in your prioritisation queue.

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

That depends on your deployment topology. For high-availability or clustered setups you 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.

References

• Official vendor advisory: https://git.kernel.org/stable/c/e34a33d5d7e87399af0a138bb32f6a3e95dd83d2
• NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37924
• CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• https://git.kernel.org/stable/c/b447463562238428503cfba1c913261047772f90
• https://git.kernel.org/stable/c/e18c616718018dfc440e4a2d2b94e28fe91b1861
• https://git.kernel.org/stable/c/28c756738af44a404a91b77830d017bb0c525890

*Written by Sai Kiran Pandrala on 2026-05-25. Sourced from the official vendor advisory, the NVD record, and the CISA KEV listing. Always confirm against the vendor's advisory before applying changes in production.*