Public proof of conceptFix available

CVE-2021-4154

Q: Is CVE-2021-4154 actively exploited?

Active exploitation of CVE-2021-4154 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-4154?

CVE-2021-4154 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

A public proof of concept exists; no exploitation attested.

Published2022-02-04
WeaknessCWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A use-after-free flaw was found in cgroup1_parse_param in kernel/cgroup/cgroup-v1.c in the Linux kernel's cgroup v1 parser. A local attacker with a user privilege could cause a privilege escalation by exploiting the fsconfig syscall parameter leading to a container breakout and a denial of service on the system.

Timeline

dates in UTC

2022-02-0423:15CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-4154?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-4154?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Netapp hci baseboard management controller

Branch	Affected	Fixed in	Source
—	= h300e	no fix published	NVD
—	= h300s	no fix published	NVD
—	= h410s	no fix published	NVD
—	= h500e	no fix published	NVD
—	= h500s	no fix published	NVD
—	= h700e	no fix published	NVD
—	= h700s	no fix published	NVD

Linux linux kernel

Branch	Affected	Fixed in	Source
5.13	≥ 5.13, < 5.13.4	5.13.4	NVD
5.x	≥ 5.11, < 5.12.19	5.12.19	NVD
5.x	≥ 5.5, < 5.10.52	5.10.52	NVD
5.x	≥ 5.1, < 5.4.134	5.4.134	NVD
5.14	= 5.14	no fix published	NVD

Redhat enterprise linux

Branch	Affected	Fixed in	Source
8.0	= 8.0	no fix published	NVD

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

kernel-tools-libs-develAlmaLinux:8all versions · fixed in 4.18.0-348.20.1.el8_5

Full record on NVD

Fix

Advisories and patches

bugzilla.redhat.comPatch
git.kernel.orgPatch · Vendor Advisory

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 2 repositories, unverifiedMarkakd/CVE-2021-4154veritas501/CVE-2021-4154

Sources

NVDCVSS 3.18.8read 2026-10-23
NVDCVSS 2.07.2read 2026-10-23
CNAweakness (CWE)CWE-416read 2026-10-23
NVDweakness (CWE)CWE-416read 2026-10-23
FIRST EPSSEPSS score1.2 %2026-10-23
PoC-in-GitHubproof of concept2read 2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Published: 2022-02-04
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-4154?

Is CVE-2021-4154 actively exploited?

Active exploitation of CVE-2021-4154 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-4154?

CVE-2021-4154 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

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