CVE-2025-38724: Linux Kernel nfsd use-after-free in nfsd4_setclientid_confirm

CVE-2025-38724 · Severity: critical · CVSS 9.8 · Published 2025-09-04

A vulnerability exists in the Linux kernel's Network File System (NFS) server component, which is used to share files across a network. A flaw in how the server handles client identification requests can lead to a system crash or allow unauthorized access to memory. This could result in a complete service outage or the theft of sensitive data stored on the server.

Technologies: Linux Kernel, Siemens SIMATIC CN 4100, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP. Vendors: Linux, Siemens.

Quick answers

Is CVE-2025-38724 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-38724 being exploited in the wild.
How severe is CVE-2025-38724?
Critical severity, with a CVSS score of 9.8, published 4 September 2025.
Which products and versions are affected?
Linux Kernel 3.17 to 5.4.297, 5.5 to 5.10.241, 5.11 to 5.15.190, 5.16 to 6.1.149, 6.2 to 6.6.103, 6.7 to 6.12.43, 6.13 to 6.15.11, 6.16 to 6.16.2, versions prior to 6.14-rc1 (fixed in various stable branches); Siemens SIMATIC CN 4100 versions prior to V5.0; Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5 and later.
Is there a fix for CVE-2025-38724?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2025-38724 attacked?
It is attacked over the network or with local access, in an operating system.
Am I affected by CVE-2025-38724?
Check whether you run Linux Kernel, Siemens SIMATIC CN 4100 or Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A use-after-free (UAF) vulnerability exists in the Linux kernel's NFSD (NFS server) implementation within the nfsd4_setclientid_confirm() function. The root cause is a failure to check the return value of get_client_locked(), allowing a SETCLIENTID_CONFIRM request to race with a confirmed client's expiration. If the race occurs, the system may attempt to use a reference to a client object that has already been freed. An attacker can exploit this via network-based NFS requests to cause a kernel panic (DoS) or potentially achieve arbitrary code execution. Patches have been released across multiple stable kernel branches (e.g., 6.1, 6.6, 6.10, 6.11).

Affected products

  • Linux Linux Kernel versions prior to 6.14-rc1 (fixed in various stable branches)
  • Siemens SIMATIC CN 4100 versions prior to V5.0
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5 and later

Timeline

  • 2025-06-04: other: Initial patch authored
  • 2025-09-04: disclosed: CVE published

References

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