PT-2021-7118 · Linux+2 · Linux Kernel+2

Pedro Sampaio · Published 2021-09-16 · Updated 2026-03-14 · CVE-2021-4023

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 5.15-rc1

Description The issue is related to the io-workqueue implementation in the Linux kernel, which lacks protection of internal data. This can be exploited to cause a denial of service. A local user with permissions to execute io-uring requests can potentially crash the system by triggering the submission of new io-uring operations during a shortage of free space, leading to a kernel panic.

Recommendations For Linux kernel versions prior to 5.15-rc1, update to version 5.15-rc1 or later to resolve the issue. As a temporary workaround, consider restricting access to io-uring requests to minimize the risk of exploitation.

Fix

Information Disclosure

Weakness Enumeration

CWE-200

Related Identifiers

ALT-PU-2021-2824

ALT-PU-2021-2926

ALT-PU-2021-3041

ALT-PU-2021-3563

ALT-PU-2021-3573

ALT-PU-2022-1240

ALT-PU-2022-1419

ALT-PU-2022-1421

ALT-PU-2023-1814

ALT-PU-2023-4894

BDU:2022-03403

CVE-2021-4023

Affected Products

Alt Linux

Debian

Linux Kernel

References · 14

• https://ubuntu.com/security/CVE-2021-4023 · Vendor Advisory
• https://bugzilla.redhat.com/show_bug.cgi?id=2026484 · Patch
• https://wiki.astralinux.ru/astra-linux-se81-bulletin-20241206SE81 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-4023 · Security Note
• https://osv.dev/vulnerability/ROOT-OS-DEBIAN-11-CVE-2021-4023 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-4023 · Security Note
• https://osv.dev/vulnerability/CVE-2021-4023 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-4023 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2021-4023 · Vendor Advisory
• https://bdu.fstec.ru/vul/2022-03403 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-4023 · Vendor Advisory
• https://lkml.org/lkml/2021/9/8/64 · Note
• https://git.kernel.dk/cgit/linux-block/commit/?h=io_uring-5.15&id=713b9825a4c47897f66ad69409581e7734a8728e · Note
• https://access.redhat.com/security/cve/CVE-2021-4023 · Note