CVE-2021-47179Network attack vector

Kernel crash via NULL layout-range dereference

Published Mar 25, 2024 · Updated Aug 5, 2026

NULL pointer dereference in Linux NFSv4 clients allows remote attackers to crash the kernel during pNFS layout return processing. The pnfs_mark_matching_lsegs_return() function dereferences a NULL pnfs_layout_range supplied by _pnfs_return_layout(), producing a kernel oops. The affected path is exercised during NFSv4.1 or NFSv4.2 pNFS operations; the bounded consequence is host service interruption.

CVSS severity7.5
High
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Linux NFSv4 clients allows remote attackers to crash the kernel during pNFS layout return processing. The pnfs_mark_matching_lsegs_return() function dereferences a NULL pnfs_layout_range supplied by _pnfs_return_layout(), producing a kernel oops. The affected path is exercised during NFSv4.1 or NFSv4.2 pNFS operations; the bounded consequence is host service interruption.

The record

CVE
CVE-2021-47179
Published
Mar 25, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 25, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=2fafe7d5047f98791afd9a1d90d2afb70debc590 <f9890652185b72b8de9ebeb4406037640b6e1b53
  2. Affected versionversion=4.14.233 <4.14.235
  3. Affected versionversion=4.19.191 <4.19.193
  4. Affected versionversion=4.9.269 <4.9.271
  5. Affected versionversion=5.10.36 <5.10.42
  6. Affected versionversion=5.11.20 <5.12
  7. Affected versionversion=5.12.3 <5.12.9
  8. Affected versionversion=5.4.118 <5.4.124
  9. Affected versionversion=6be0e4b59314e4a836495f6ffdc5d2c5b079deeb <aba3c7795f51717ae316f3566442dee7cc3eeccb
  10. Affected versionversion=7b7b9774643220e53eef58c15bb29bd4182fe053 <42637ca25c7d7b5a92804a679af5192e8c1a9f48
  11. Affected versionversion=7e65ea887d0c0997f3053acd91a027af45e71c5b <b090d110e66636bca473fd8b98d5c97b555a965a
  12. Affected versionversion=80e34f4957ec3010c85f9bb0b568a8d46acdf535 <4e1ba532dbc1a0e19fc2458d74ab8d98680c4e42
  13. Affected versionversion=96260bde1ea8ae31a5402fe506abbb8951d5a42c
  14. Affected versionversion=9ffa7967f9379a0a1b924e9ffeda709d72237da7 <39785761feadf261bc5101372b0b0bbaf6a94494
  15. Affected versionversion=de144ff4234f935bd2150108019b5d87a90a8a96 <a421d218603ffa822a0b8045055c03eae394a7eb

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2fafe7d5047f98791afd9a1d90d2afb70debc590 <f9890652185b72b8de9ebeb4406037640b6e1b53; version=4.14.233 <4.14.235; version=4.19.191 <4.19.193; version=4.9.269 <4.9.271; version=5.10.36 <5.10.42; version=5.11.20 <5.12; version=5.12.3 <5.12.9; version=5.4.118 <5.4.124; version=6be0e4b59314e4a836495f6ffdc5d2c5b079deeb <aba3c7795f51717ae316f3566442dee7cc3eeccb; version=7b7b9774643220e53eef58c15bb29bd4182fe053 <42637ca25c7d7b5a92804a679af5192e8c1a9f48; version=7e65ea887d0c0997f3053acd91a027af45e71c5b <b090d110e66636bca473fd8b98d5c97b555a965a; version=80e34f4957ec3010c85f9bb0b568a8d46acdf535 <4e1ba532dbc1a0e19fc2458d74ab8d98680c4e42; version=96260bde1ea8ae31a5402fe506abbb8951d5a42c; version=9ffa7967f9379a0a1b924e9ffeda709d72237da7 <39785761feadf261bc5101372b0b0bbaf6a94494; version=de144ff4234f935bd2150108019b5d87a90a8a96 <a421d218603ffa822a0b8045055c03eae394a7eb

Published CVSS scores

7.5kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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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