CVE-2025-39841: Linux Kernel lpfc use-after-free in deferred receive path

CVE-2025-39841 · Severity: critical · CVSS 9.8 · Published 2025-09-19

A vulnerability exists in the Linux kernel's Emulex LightPulse Fibre Channel (lpfc) driver, which manages high-performance storage connections. A flaw in how the system handles data buffers could allow an attacker to trigger a system crash or potentially execute unauthorized code. This could lead to a total loss of system availability or the compromise of sensitive data stored on connected storage networks.

Technologies: Linux Kernel, Siemens RUGGEDCOM RST2428P, Siemens SCALANCE XC-300, Siemens SCALANCE XC-400, Siemens SCALANCE XR-300, Siemens SCALANCE XR-500 family, Siemens SCALANCE XR-500WG. Vendors: Linux, Siemens.

Quick answers

Is CVE-2025-39841 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-39841 being exploited in the wild.
How severe is CVE-2025-39841?
Critical severity, with a CVSS score of 9.8, published 19 September 2025.
Which products and versions are affected?
Linux Kernel 5.1 to 5.4.299, 5.5 to 5.10.243, 5.11 to 5.15.192, 5.16 to 6.1.151, 6.2 to 6.6.105, 6.7 to 6.12.46, 6.13 to 6.16.6; Linux Kernel n/a; Siemens RUGGEDCOM RST2428P < V3.3; Siemens SCALANCE XC-300 < V3.3.
Is there a fix for CVE-2025-39841?
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-2025-39841 attacked?
It is attacked over the network or with local access, in an operating system.
Am I affected by CVE-2025-39841?
Check whether you run Linux Kernel, Linux Kernel, Siemens RUGGEDCOM RST2428P or one of the others listed 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 lpfc driver within the `lpfc_nvmet_defer_rcv` function. The root cause is an incorrect buffer release sequence where the Receive Queue (RQ) buffer was freed before the associated context pointer was cleared under a spinlock. This creates a race condition window where concurrent execution paths, such as ABTS or the repost path, could attempt to access or release the same pointer, resulting in a double-free or UAF. Attackers could potentially exploit this via network-based storage traffic to cause a kernel panic or achieve privilege escalation. Patches have been released for various stable kernel branches to ensure the pointer is detached under lock before the buffer is freed.

Affected products

  • Linux Linux Kernel n/a
  • Siemens RUGGEDCOM RST2428P < V3.3
  • Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family < V3.3

Timeline

  • 2025-08-28: other: Patch submitted by developer
  • 2025-09-19: disclosed: CVE published

References

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