CVE-2021-3489

Name: CVE-2021-3489
Creator: NVD / NIST
Published: 2021-06-04T02:15:07.047+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.55%

Last modified Jun 17, 2026

CVE-2021-3489 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not check that the allocated size was smaller than the ringbuf size, allowing an attacker to perform out-of-bounds writes within the kernel and therefore, arbitrary code execution. This issue was fixed via commit 4b81ccebaeee ("bpf, ringbuf: Deny reserve of buffers larger than ringbuf") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. EPSS estimates a 0.55% chance of exploitation in the next 30 days.

Description

The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not check that the allocated size was smaller than the ringbuf size, allowing an attacker to perform out-of-bounds writes within the kernel and therefore, arbitrary code execution. This issue was fixed via commit 4b81ccebaeee ("bpf, ringbuf: Deny reserve of buffers larger than ringbuf") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced via 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") (v5.8-rc1).

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.55%

41.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 5.8, < 5.10.37
Linux	Linux Kernel	>= 5.11, < 5.11.21
Linux	Linux Kernel	>= 5.12, < 5.12.4
Linux	Linux Kernel	5.13
Canonical	Ubuntu Linux	20.04
Canonical	Ubuntu Linux	20.10
Canonical	Ubuntu Linux	21.04

References

https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=4b81ccebaeee885ab1aa1438133f2991e3a2b6eaPatch, Vendor Advisory
https://security.netapp.com/advisory/ntap-20210716-0004/Third Party Advisory
https://ubuntu.com/security/notices/USN-4949-1Third Party Advisory
https://ubuntu.com/security/notices/USN-4950-1Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/05/11/10Mailing List, Third Party Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-590/Third Party Advisory, VDB Entry
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=4b81ccebaeee885ab1aa1438133f2991e3a2b6eaPatch, Vendor Advisory
https://security.netapp.com/advisory/ntap-20210716-0004/Third Party Advisory
https://ubuntu.com/security/notices/USN-4949-1Third Party Advisory
https://ubuntu.com/security/notices/USN-4950-1Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/05/11/10Mailing List, Third Party Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-590/Third Party Advisory, VDB Entry

Timeline

Published: Jun 4, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3489?

How severe is CVE-2021-3489?

CVE-2021-3489 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.55% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3489?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3489?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST