CVE-2021-20239

Name: CVE-2021-20239
Creator: NVD / NIST
Published: 2021-05-28T11:15:08.003+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 3.3/10EPSS 0.26%

Last modified Jun 17, 2026

CVE-2021-20239 is a low-severity vulnerability rated 3.3/10 on the CVSS scale. A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. EPSS estimates a 0.26% chance of exploitation in the next 30 days.

Description

A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality.

Metrics

CVSS 3.1

3.3/10

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

EPSS Probability

0.26%

16.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 5.4.92
Redhat	Enterprise Linux	5.0
Redhat	Enterprise Linux	6.0
Redhat	Enterprise Linux	8.0
Fedoraproject	Fedora	33

References

https://bugzilla.redhat.com/show_bug.cgi?id=1923636Issue Tracking, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1923636Issue Tracking, Third Party Advisory

Timeline

Published: May 28, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20239?

How severe is CVE-2021-20239?

CVE-2021-20239 has a CVSS score of 3.3/10 (LOW severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20239?

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-2021-20239?

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

Scan your code now

Source: NVD / NIST