CVE-2021-4154

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.

Published: 2022-02-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-4154 is rated Moderate Risk (58.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.21%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-4154

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.77% 1.21% +0.44%
2 2025-12-20 0.72% 0.77% +0.05%
3 2025-12-01 — 0.72% —

Full EPSS history (21 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-4154

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.0 6.0 [email protected]
7.2 2.0 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 3.9 10.0 [email protected]

Weakness enumeration for CVE-2021-4154

OS Trackers for CVE-2021-4154

vendor priority summary link
debian not yet assigned CVE-2021-4154 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-4154
redhat high — https://access.redhat.com/security/cve/CVE-2021-4154
suse high CVE-2021-4154 severity important: SUSE including 398 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 818 product×package rows across 92 product lines (Container suse/sle-micro-rancher/5.2, HPE Helion OpenStack 8, … (92 product lines)): Fixed 443, Known Affected 190, Known Not Affected 185. https://www.suse.com/security/cve/CVE-2021-4154/
ubuntu medium CVE-2021-4154 medium priority: Ubuntu including 167 source packages (linux, linux-allwinner, …), 2101 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1627, not-affected 236, released 182, ignored 56. https://ubuntu.com/security/CVE-2021-4154

Affected software / configurations for CVE-2021-4154

Vendor Product Version Raw CPE
linux linux_kernel >= 5.1, < 5.4.134 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.5, < 5.10.52 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.12.19 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.13, < 5.13.4 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 5.14 cpe:2.3:o:linux:linux_kernel:5.14:rc1:*:*:*:*:*:*
redhat virtualization 4.0 cpe:2.3:a:redhat:virtualization:4.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:-:*:*:*
netapp hci_baseboard_management_controller h300e cpe:2.3:a:netapp:hci_baseboard_management_controller:h300e:*:*:*:*:*:*:*
netapp hci_baseboard_management_controller h300s cpe:2.3:a:netapp:hci_baseboard_management_controller:h300s:*:*:*:*:*:*:*
netapp hci_baseboard_management_controller h410s cpe:2.3:a:netapp:hci_baseboard_management_controller:h410s:*:*:*:*:*:*:*
netapp hci_baseboard_management_controller h500e cpe:2.3:a:netapp:hci_baseboard_management_controller:h500e:*:*:*:*:*:*:*
netapp hci_baseboard_management_controller h500s cpe:2.3:a:netapp:hci_baseboard_management_controller:h500s:*:*:*:*:*:*:*
netapp hci_baseboard_management_controller h700e cpe:2.3:a:netapp:hci_baseboard_management_controller:h700e:*:*:*:*:*:*:*
netapp hci_baseboard_management_controller h700s cpe:2.3:a:netapp:hci_baseboard_management_controller:h700s:*:*:*:*:*:*:*

References for CVE-2021-4154

cvelogic Threat Intelligence