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NTAP-20260417-0008 — CVE-2026-31402 Linux Kernel Vulnerability in NetApp Products

Published 2026-04-17 · Updated 2026-09-03 · Status: Interim · Exploitation: Public · Severity: CRITICAL 9.8 · ONTAP affected: Yes

Official advisory: NTAP-20260417-0008 on security.netapp.com ↗. Affected versions, fixed releases, and workarounds live there — this page is a summary.

Product family: ONTAP · Other NetApp products · NetApp Console / BlueXP · SolidFire / NetApp HCI  |  ONTAP-relevant  |  highest CVSS: 9.8

CVEs in this advisory

What the CVE records say

CVE-2026-31402 — In the Linux kernel, the following vulnerability has been resolved: nfsd: fix heap overflow in NFSv4.0 LOCK replay cache The NFSv4.0 replay cache uses a fixed 112-byte inline buffer (rp_ibuf[NFSD4_REPLAY_ISIZE]) to store encoded operation responses. This size was calculated based on OPEN responses and does not account for LOCK denied responses, which include the conflicting lock owner as a variable-length field up to 1024 bytes (NFS4_OPAQUE_LIMIT). When a LOCK operation is denied due to a conflict with an existing lock that has a large owner, nfsd4_encode_operation() copies the full encoded response into the undersized replay buffer via read_bytes_from_xdr_buf() with no bounds check. This results in a slab-out-of-bounds write of up to 944 bytes past the end of the buffer, corrupting adjacent heap memory. This can be triggered remotely by an unauthenticated attacker with two cooperating NFSv4.0 clients: one sets a lock with a large owner string, then the other requests a conflicting lock to provoke the denial. We could fix this by increasing NFSD4_REPLAY_ISIZE to allow for a full opaque, but that would increase the size of every stateowner, when most lockowners are not that large. Instead, fix this by checking the encoded response length against NFSD4_REPLAY_ISIZE before copying into the replay buffer. If the response is too large, set rp_buflen to 0 to skip caching the replay payload. The status is still cached, and the client already received the correct response on the original request.

Impact

Successful exploitation of this vulnerability could lead to disclosure of sensitive information, addition or modification of data, or Denial of Service (DoS).

Affected products

Official fixes

References

What to do

  1. Check the affected products listed above against the official advisory's affected-versions table — that is where the exact ONTAP 9 release, ONTAP tool, or management product versions are named.
  2. If affected and a fixed release exists, plan the upgrade — see the ONTAP upgrade runbook.
  3. If exploitation is listed as "active", treat remediation as urgent and review exposure (management LIFs, ONTAP S3, SnapMirror endpoints).
  4. Harden in parallel: security hardening baseline and ransomware protection on ONTAP.

Related reading

Browse all ONTAP CVEs → · Security hub