CVE-2021-3679

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-08-05 · updated 2026-06-17
Weakness: CWE-400

Description

A lack of CPU resource in the Linux kernel tracing module functionality in versions prior to 5.14-rc3 was found in the way user uses trace ring buffer in a specific way. Only privileged local users (with CAP_SYS_ADMIN capability) could use this flaw to starve the resources causing denial of service.

Affected products

Debian Linux: 9.0, 10.0
Linux kernel: before 5.14; 5.14, 5.14-rc1, 5.14-rc2 — fixed in 5.14
Red Hat Enterprise Linux: 8.0

How to fix

Upgrade to a fixed version: Linux kernel 5.14. Check the vendor advisory for mitigations.

References

https://bugzilla.redhat.com/show_bug.cgi?id=1989165
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=67f0d6d9883c13174669f88adac4f0ee656cc16a
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html
https://www.debian.org/security/2021/dsa-4978
https://bugzilla.redhat.com/show_bug.cgi?id=1989165
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=67f0d6d9883c13174669f88adac4f0ee656cc16a
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html
https://www.debian.org/security/2021/dsa-4978

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