Vulnary
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Critical· 9.8official fix available

CVE-2026-31402

A critical flaw in the Linux kernel’s NFSv4.0 replay cache can let an attacker overwrite memory on the server. The bug happens when a lock request is denied and the kernel copies too much data into a small buffer, potentially allowing arbitrary code execution. The issue has been fixed in recent kernel releases.

publishedApr 3, 2026
last modifiedJul 24, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
39th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 25, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

All Linux kernel versions that include the NFSv4.0 implementation, such as 2.6.12 and 7.0, are affected. The vulnerability applies to any system running an NFSv4.0 server.

02

Real-world impact

An attacker could trigger the flaw by coordinating two NFSv4.0 clients, causing the server to write beyond the bounds of a heap buffer. This could corrupt memory, leading to denial of service or arbitrary code execution on the NFS server.

03

Why this severity

The CVSS score of 9.8 reflects that the flaw can be exploited remotely without authentication, requires no user interaction, and can compromise confidentiality, integrity, and availability of the affected system.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade the Linux kernel to a version that includes the CVE-2026-31402 fix.
  2. 02Reboot the system so the new kernel is loaded.

NVD description indicates the vulnerability has been resolved.

05

Timeline

  1. Apr 3, 2026 · Apr 3, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 24, 2026 · 11d ago
    Advisory updated
    The NVD record was last revised.
  3. Jul 26, 2026 · 10d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →