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Fencer Vulns
medium 5.5

CVE-2021-4023 json

A flaw was found in the io-workqueue implementation in the Linux kernel versions prior to 5.15-rc1.

published 2022-03-09 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-33926

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

A flaw was found in the io-workqueue implementation in the Linux kernel versions prior to 5.15-rc1. The kernel can panic when an improper cancellation operation triggers the submission of new io-uring operations during a shortage of free space. This flaw allows a local user with permissions to execute io-uring requests to possibly crash the system.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.15.3-1

debian advisories DEBIAN-CVE-2021-4023

  • linux-lts Arch Linux 5.15.2-1
  • linux Arch Linux 5.15.arch1-1
  • linux-zen Arch Linux 5.15.zen1-1
  • linux-hardened Arch Linux 5.15.5.hardened1-1

arch linux advisories AVG-1741AVG-2522AVG-2523AVG-2524

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-4023 updated cvss 4.7

kernel: Improper IO-uring request cancellation operation allows local users to cause a crash

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Affected products

  • n/a kernel

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.