CVE-2021-20268: Input Validation

Published Feb 2, 2021
·
Updated

A flaw was found in the Linux kernel. Improper Input Validation in the handling of eBPF programs may lead to privilege escalation.

References:

https://www.zerodayinitiative.com/advisories/ZDI-21-101/

Other sources

An out-of-bounds access flaw was found in the Linux kernel's implementation of the eBPF code verifier in the way a user running the eBPF script calls devmapinitmap or sockmapalloc. This flaw allows a local user to crash the system or possibly escalate their privileges. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Launchpad

Affected Software

3 affected componentsFixes available
redhat/kernel<5.10.10
5.10.10
Linux Linux kernel<5.10.10
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.22-16.12.25-1

Remediation

Mitigation

If loading of BPF programs by unprivileged users is not needed, set the following sysctl, or disable it permanently in /etc/sysctl.d/: kernel.unprivileged_bpf_disabled = 1

Event History

Mar 9, 2021
CVE Published
via MITRE·05:16 PM
Data Sourced
via MITRE·05:16 PM
DescriptionWeakness
Jan 11, 2024
Data Sourced
via Launchpad·11:54 PM
Description
Sep 16, 2024
Data Sourced
via Ubuntu·01:24 AM
RemedyDescriptionSeverityAffected Software
Apr 8, 2025
Data Sourced
via Debian·04:23 AM
DescriptionAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2021-20268?

CVE-2021-20268 has been classified with a high severity rating due to its potential for privilege escalation.

2

How do I fix CVE-2021-20268?

To remediate CVE-2021-20268, update the Linux kernel to versions 5.10.10 or newer for Red Hat or the specified patched versions for Debian.

3

Which Linux distributions are affected by CVE-2021-20268?

CVE-2021-20268 affects multiple Linux distributions including Red Hat and Debian versions prior to the specified patched releases.

4

What type of vulnerability is CVE-2021-20268?

CVE-2021-20268 is an improper input validation vulnerability in the handling of eBPF programs within the Linux kernel.

5

Can CVE-2021-20268 be exploited remotely?

Exploitation of CVE-2021-20268 typically requires local access to the system, suggesting it is not directly exploitable remotely.

Contact

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