#VU92756 Improper locking in Linux kernel - CVE-2021-38203

Vulnerability identifier: #VU92756

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-2021-38203

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 (DoS) attack.

btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.

Mitigation
Install update from vendor's repository.

Vulnerable software versions

Linux kernel: All versions

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External links
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4
https://github.com/torvalds/linux/commit/1cb3db1cf383a3c7dbda1aa0ce748b0958759947
https://security.netapp.com/advisory/ntap-20210902-0010/

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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.