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Fencer Vulns
medium 5.5

CVE-2021-4218 json

A flaw was found in the Linux kernel’s implementation of reading the SVC RDMA counters.

published 2022-08-24 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-34076

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

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.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-4218 updated cvss 5.5

kernel: sysctl parameter read causes kernel panic ( rpcrdma module )

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, python-perf, kernel-kdump, kernel-tools, +3 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-core, kernel-tools, python3-perf, +17 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugs.centos.org https://bugs.centos.org/view.php?id=18395 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • n/a kernel

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.