CVE-2025-40084

In the Linux kernel, the following vulnerability has been resolved: ksmbd: transport_ipc: validate payload size before reading handle handle_response() dereferences the payload as a 4-byte handle without verifying that the declared payload size is at least 4 bytes. A malformed or truncated message from ksmbd.mountd can lead to a 4-byte read past the declared payload size. Validate the size before dereferencing. This is a minimal fix to guard the initial handle read.

Package Linux Kernel
Published 2025-10-29
Last modified 2026-04-15
Patch available
Yes

Affected versions

Linux kernel versions 5.15 and later are affected. Fixed in 6.1.158, 6.6.115, 6.12.56, 6.17.6, 6.18 and their respective stable series.

Affected from
≥ 5.15
Fixed in
✓ 6.1.158 6.1.x ✓ 6.6.115 6.6.x ✓ 6.12.56 6.12.x ✓ 6.17.6 6.17.x ✓ 6.18

References

The following references provide additional information about CVE-2025-40084 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Frequently asked questions

  • What is CVE-2025-40084?

    CVE-2025-40084 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.15 onward and has been patched in 6.1.158, 6.6.115, 6.12.56 and others. CVE-2025-40084 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • Is there a patch available for CVE-2025-40084?

    Yes — CVE-2025-40084 has been patched. Fixed versions include 6.1.158, 6.6.115, 6.12.56 and others. If you are running Linux kernel 5.15 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-40084 actively exploited?

    No — CVE-2025-40084 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.