CVE-2021-4154

HIGH

Linux Kernel >=5.1 <5.4.134 - Use-After-Free in cgroup v1 Parser

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2021-4154. PoCs published by Markakd, veritas501.

AI-analyzed exploit summary This repository contains a working proof-of-concept exploit for CVE-2021-4154, a use-after-free vulnerability in the Linux kernel's filesystem layer. The exploit leverages race conditions and memory manipulation to achieve local privilege escalation (LPE) on vulnerable kernels.

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.

Exploits (2)

nomisec WORKING POC 67 stars
by Markakd · poc
https://github.com/Markakd/CVE-2021-4154

This repository contains a working proof-of-concept exploit for CVE-2021-4154, a use-after-free vulnerability in the Linux kernel's filesystem layer. The exploit leverages race conditions and memory manipulation to achieve local privilege escalation (LPE) on vulnerable kernels.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: Linux kernel (various distributions and versions as listed in README)
No auth needed
Prerequisites: Vulnerable Linux kernel version · Local access to the target system
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 7 stars
by veritas501 · poc
https://github.com/veritas501/CVE-2021-4154

This is a working exploit for CVE-2021-4154, a use-after-free vulnerability in the Linux kernel's fsconfig syscall. The PoC leverages race conditions and namespace isolation to achieve local privilege escalation by corrupting file descriptors.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: Linux kernel (specific version not specified)
No auth needed
Prerequisites: Linux kernel with vulnerable fsconfig implementation · Ability to execute unprivileged code
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (4)

Core 4
Core References
Issue Tracking, Patch, Third Party Advisory x_refsource_misc
https://bugzilla.redhat.com/show_bug.cgi?id=2034514
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20220225-0004/

Scores

CVSS v3 8.8
EPSS 0.0121
EPSS Percentile 64.3%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Details

CWE
CWE-416
Status published
Products (11)
linux/linux_kernel 5.14 rc1
linux/linux_kernel 5.1 - 5.4.134
netapp/hci_baseboard_management_controller h300e
netapp/hci_baseboard_management_controller h300s
netapp/hci_baseboard_management_controller h410s
netapp/hci_baseboard_management_controller h500e
netapp/hci_baseboard_management_controller h500s
netapp/hci_baseboard_management_controller h700e
netapp/hci_baseboard_management_controller h700s
redhat/enterprise_linux 8.0
... and 1 more
Published Feb 04, 2022
Tracked Since Feb 18, 2026