CVE-2021-47322

Kernel crash via unchecked pNFS operations pointer

Published May 21, 2024 · Updated May 11, 2026

Denial of service in the Linux NFSv4 client allows local users to crash the kernel through O_DIRECT writes after a failed pNFS attempt. pnfs_mark_request_commit() dereferences fl_cinfo->ops without checking whether the operations table is NULL when rescheduling direct writes. Reachability requires local write access to an NFSv4 pNFS mount, O_DIRECT I/O, and a failed pNFS operation; the resulting NULL-pointer dereference causes a kernel Oops.

CVSS severity7.8
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux NFSv4 client allows local users to crash the kernel through O_DIRECT writes after a failed pNFS attempt. pnfs_mark_request_commit() dereferences fl_cinfo->ops without checking whether the operations table is NULL when rescheduling direct writes. Reachability requires local write access to an NFSv4 pNFS mount, O_DIRECT I/O, and a failed pNFS operation; the resulting NULL-pointer dereference causes a kernel Oops.

The record

CVE
CVE-2021-47322
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.7
  2. Affected versionversion=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <3731d44bba8e0116b052b1b374476c5f6dd9a456
  3. Affected versionversion=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <5c7ef8a3705542136a1e19b070e951f0730b2153
  4. Affected versionversion=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <7aec9f862411906f8c27071ba65a1e110ad7d2fd
  5. Affected versionversion=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <7c96a2ee45be41d5a167e6332d202086752c36bb

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.7; version=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <3731d44bba8e0116b052b1b374476c5f6dd9a456; version=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <5c7ef8a3705542136a1e19b070e951f0730b2153; version=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <7aec9f862411906f8c27071ba65a1e110ad7d2fd; version=9c455a8c1e146dac3a6d1405fe6a7096177b9546 <7c96a2ee45be41d5a167e6332d202086752c36bb

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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