#VU55262 Permissions, Privileges, and Access Controls in Linux kernel - CVE-2020-36311

Vulnerability identifier: #VU55262

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-2020-36311

CWE-ID: CWE-264

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.

The vulnerability exists due to an error in arch/x86/kvm/svm/sev.c in Linux kernel, which allows soft lockup by triggering destruction of a large SEV VM (which requires unregistering many encrypted regions).

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.9.0, 5.9.0

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External links
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7be74942f184fdfba34ddd19a0d995deb34d4a03
https://lists.debian.org/debian-lts-announce/2021/07/msg00015.html

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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.