Denial of service in Linux kernel timer queue implementation

1) Improper Initialization

EUVDB-ID: #VU58208

Risk: Low

CVSSv3.1: 4.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20317

CWE-ID: CWE-665 - Improper Initialization

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to improper initialization the Linux kernel. A corrupted timer tree causes the task wakeup to be missing in the timerqueue_add function in lib/timerqueue.c. A local user can run a specially crafted application to crash the kernel.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.4

External links

http://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=511885d7061eda3eb1faf3f57dcc936ff75863f1
http://bugzilla.redhat.com/show_bug.cgi?id=2005258

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.