#VU64071 Improper locking in Linux kernel - CVE-2021-4149

Vulnerability identifier: #VU64071

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-4149

CWE-ID: CWE-667

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 perform a denial of service attack (DoS) on the target system.

The vulnerability exists in btrfs_alloc_tree_b in fs/btrfs/extent-tree.c in the Linux kernel due to an improper lock operation in btrfs. A local user can exploit this vulnerability to cause a deadlock, resulting in a denial of service condition.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.15, 5.15

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External links
https://lkml.org/lkml/2021/9/13/2565
https://bugzilla.redhat.com/show_bug.cgi?id=2026485
https://lkml.org/lkml/2021/10/18/885

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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.