What is CVE-2021-4218?

CVE-2021-4218 is a medium-severity vulnerability in Linux Kernel, classified under Improper Initialization. CVSS score: 5.5/10. Published 2022-08-24.

How severe is CVE-2021-4218?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Linux Kernel

CVE-2021-4218

A flaw was found in the Linux kernel’s implementation of reading the SVC RDMA counters. Reading the counter sysctl panics the system. This flaw allows a local attacker with local access to cause a denial of service while the system reboots. The issue is specific to CentOS/RHEL.

Vulnerability class: Dirty Pipe (CVE-2022-0847)

Published 2022-08-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (20.7th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 20.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Linux Kernel
Kernel

Weakness classification (CWE)

CWE-665 — Improper Initialization

References

bugs.centos.org/view.php (Exploit, Third Party Advisory)
bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
access.redhat.com/security/cve/CVE-2021-4218 (Third Party Advisory)

Frequently asked questions

What is CVE-2021-4218?: CVE-2021-4218 is a medium-severity vulnerability in Linux Kernel, classified under Improper Initialization. CVSS score: 5.5/10. Published 2022-08-24.
How severe is CVE-2021-4218?: Medium severity. CVSS v3 base score is 5.5 out of 10.