CVE-2021-3444: Linux kernel bpf verifier incorrect mod32 truncation
First published: Tue Mar 23 2021(Updated: )
Last updated 11 April 2025
Credit: security@ubuntu.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | <5.4.101 | |
| Linux Kernel | >=5.5.0<5.10.19 | |
| Linux Kernel | >=5.11<5.11.2 | |
| Debian Linux | =9.0 | |
| Ubuntu | =14.04 | |
| Ubuntu | =16.04 | |
| Ubuntu | =18.04 | |
| Ubuntu | =20.04 | |
| debian/linux | 5.10.223-1 5.10.234-1 6.1.129-1 6.1.133-1 6.12.21-1 6.12.22-1 |
Remedy
Apply or update to a kernel that contains the commit 9b00f1b78809 ("bpf: Fix truncation handling for mod32 dst reg wrt zero").
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Reference Links
- http://packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075-1.html
- http://packetstormsecurity.com/files/164950/Kernel-Live-Patch-Security-Notice-LSN-0082-1.html
- http://www.openwall.com/lists/oss-security/2021/03/23/2
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9b00f1b78809
- https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html
- https://security.netapp.com/advisory/ntap-20210416-0006/
- https://www.openwall.com/lists/oss-security/2021/03/23/2
- https://launchpad.net/bugs/cve/CVE-2021-3444
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3444
- https://nvd.nist.gov/vuln/detail/CVE-2021-3444
- https://security-tracker.debian.org/tracker/CVE-2021-3444
- https://ubuntu.com/security/CVE-2021-3444
- https://git.kernel.org/linus/9b00f1b78809309163dda2d044d9e94a3c0248a3
Frequently Asked Questions
What is the severity of CVE-2021-3444?
CVE-2021-3444 is considered to have a high severity due to its potential for exploitation leading to out-of-bounds reads in kernel memory.
How do I fix CVE-2021-3444?
To fix CVE-2021-3444, you should upgrade to the patched versions of the Linux kernel as specified by your distribution.
Which Linux kernel versions are affected by CVE-2021-3444?
CVE-2021-3444 affects kernel versions prior to 5.10.19, and also between 5.11 and 5.11.2.
Can an attacker exploit CVE-2021-3444 remotely?
CVE-2021-3444 requires a local attacker with the ability to load BPF programs, therefore it is not a remote exploit.
What are the possible impacts of CVE-2021-3444 if exploited?
The exploitation of CVE-2021-3444 can lead to unauthorized access to kernel memory, which may expose sensitive information or lead to further system compromises.
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