CVE-2021-3679 Denial of service in kernel

What is CVE-2021-3679?

CVE-2021-3679 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 5 Aug 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-835, CWE-400

Which versions are affected by CVE-2021-3679?

It affects 3 products.

Products include Debian Debian Linux, Linux kernel, Redhat Enterprise Linux.

How do I fix CVE-2021-3679?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-3679 being exploited?

There is no known exploitation of CVE-2021-3679 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

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• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-6577, DEBIAN-CVE-2021-3679, GHSA-mfgx-frfq-59jc, UBUNTU-CVE-2021-3679.