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No exploitation reportedFix available

CVE-2021-4157

No exploitation reported by the sources we read.

  • Published2022-03-25
  • Fixed in5.12.5 · 5.11.22 · 5.10.38 · 5.4.120 · 4.19.191 · 4.14.233
  • WeaknessCWE-119

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An out of memory bounds write flaw (1 or 2 bytes of memory) in the Linux kernel NFS subsystem was found in the way users use mirroring (replication of files with NFS). A user, having access to the NFS mount, could potentially use this flaw to crash the system or escalate privileges on the system.

Timeline

dates in UTC
  1. 2022-03-2519:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-4157?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-4157?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Linux linux kernel
BranchAffectedFixed in
5.12≥ 5.12, < 5.12.55.12.5
5.11≥ 5.11, < 5.11.225.11.22
5.x≥ 5.5, < 5.10.385.10.38
5.4≥ 4.20, < 5.4.1205.4.120
4.x≥ 4.15, < 4.19.1914.19.191
4.x≥ 4.10, < 4.14.2334.14.233
4.x≥ 4.5, < 4.9.2694.9.269
4.x≥ 4.0, < 4.4.2694.4.269
Oracle communications cloud native core binding support function
BranchAffectedFixed in
22.1= 22.1.1no fix published
22.1= 22.1.3no fix published
22.2= 22.2.0no fix published
Fedoraproject fedora
BranchAffectedFixed in
35.x= 35no fix published

7 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Linux linux kernel to 5.12.5 · 5.11.22 · 5.10.38 · 5.4.120 · 4.19.191 · 4.14.233 · 4.9.269 · 4.4.269

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVSS 3.18read 2026-10-23
  • NVDCVSS 2.07.4read 2026-10-23
  • CNAweakness (CWE)CWE-119read 2026-10-23
  • NVDweakness (CWE)CWE-119read 2026-10-23
  • FIRST EPSSEPSS score1.6 %2026-10-22

Technical details

CVSS v3 Vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2022-03-25
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-4157?

An out of memory bounds write flaw (1 or 2 bytes of memory) in the Linux kernel NFS subsystem was found in the way users use mirroring (replication of files with NFS). A user, having access to the NFS mount, could potentially use this flaw to crash the system or escalate privileges on the system.

Is CVE-2021-4157 actively exploited?

Active exploitation of CVE-2021-4157 has not been confirmed. Its EPSS score was 1.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-4157?

CVE-2021-4157 has a CVSS v3 base score of 8 (HIGH severity), with vector string CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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