Linux Kernel NFSv4 Server Race Condition Remote Code Execution Vulnerability

September 14th, 2026
ZDI-26-695 ZDI-CAN-30500

CVE ID

CVE-2026-89688

CVSS Score

8.5 AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected Vendors

Linux

Affected Products

Kernel

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Linux Kernel. Authentication is required to exploit this vulnerability. Furthermore, only systems with nfsd enabled are vulnerable.

The specific flaw exists within the handling of nfs4_openowner objects. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to execute code in the context of the kernel.

Additional Details

Linux has issued an update to correct this vulnerability. More details can be found at:
https://github.com/torvalds/linux/commit/5e4627d3513e60accfce9d5f4c7fa95251ef93d6

Disclosure Timeline

  • 2026-05-22 - Vulnerability reported to vendor
  • 2026-09-14 - Coordinated public release of advisory
  • 2026-09-14 - Advisory Updated

Credit

GangMin Kim

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