#VU63665 Incorrect permission assignment for critical resource in Linux kernel - CVE-2021-38198

Vulnerability identifier: #VU63665

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-2021-38198

CWE-ID: CWE-732

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 arch/x86/kvm/mmu/paging_tmpl.h incorrectly computes the access permissions of a shadow page. A local user can trigger an error to perform a denial of service attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: 5.12.3 - 5.12.4

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External links
https://github.com/torvalds/linux/commit/b1bd5cba3306691c771d558e94baa73e8b0b96b7
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.11
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.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.