CVE-2021-20268: Input Validation
First published: Tue Feb 02 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: <a href="https://www.zerodayinitiative.com/advisories/ZDI-21-101/">https://www.zerodayinitiative.com/advisories/ZDI-21-101/</a>
Credit: secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel | <5.10.10 | 5.10.10 |
| Linux Kernel | <5.10.10 | |
| debian/linux | 5.10.223-1 5.10.234-1 6.1.129-1 6.1.135-1 6.12.22-1 6.12.25-1 |
Remedy
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
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Reference Links
- https://bugzilla.redhat.com/show_bug.cgi?id=1923816
- https://lore.kernel.org/bpf/CACAyw99bEYWJCSGqfLiJ9Jp5YE1ZsZSiJxb4RFUTwbofipf0dA@mail.gmail.com/T/#m8929643e99bea9c18ed490a7bc2591145eac6444
- https://security.netapp.com/advisory/ntap-20210409-0006/
- https://launchpad.net/bugs/cve/CVE-2021-20268
- https://lore.kernel.org/bpf/CACAyw99bEYWJCSGqfLiJ9Jp5YE1ZsZSiJxb4RFUTwbofipf0dA%40mail.gmail.com/T/#m8929643e99bea9c18ed490a7bc2591145eac6444
- https://www.zerodayinitiative.com/advisories/ZDI-21-101/
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1923817
- https://git.kernel.org/linus/bc895e8b2a64e502fbba72748d59618272052a8b
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1923816#c13
- https://lkml.org/lkml/2021/1/26/735
- https://git.kernel.org/
- https://security-tracker.debian.org/tracker/CVE-2021-20268
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20268
- https://nvd.nist.gov/vuln/detail/CVE-2021-20268
- https://ubuntu.com/security/CVE-2021-20268
Frequently Asked Questions
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.
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.
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.
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.
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.
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