Vulnerability identifier: #VU63838

Vulnerability risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-4203

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

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

Vendor: Linux Foundation

Description

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

The vulnerability exists due to a use-after-free error in sock_getsockopt() function in net/core/sock.c due to SO_PEERCRED and SO_PEERGROUPS race with listen() function (and connect() function) in the Linux kernel. A local user can exploit the use-after-free error and crash the system or escalate privileges on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel:

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External links
http://lore.kernel.org/netdev/20210929225750.2548112-1-eric.dumazet@gmail.com/T/
http://bugs.chromium.org/p/project-zero/issues/detail?id=2230&can=7&q=modified-after%3Atoday-30&sort=-modified&colspec=ID%20Type%20Status%20Priority%20Milestone%20Owner%20Summary%20Modified%20Cve&cells=tiles&redir=1
http://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=35306eb23814
http://bugzilla.redhat.com/show_bug.cgi?id=2036934

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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.