Vulnerability identifier: #VU59840

Vulnerability risk: Low

CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-4154

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor:

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the cgroup1_parse_param() function in kernel/cgroup/cgroup-v1.c in Linux kernel's cgroup v1 parser. A local user can execute arbitrary code via the fsconfig syscall parameter leading to a container breakout.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

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External links
http://bugzilla.redhat.com/show_bug.cgi?id=2034514

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.