#VU63422 Use-after-free in Linux kernel - CVE-2021-45868

Vulnerability identifier: #VU63422

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-2021-45868

CWE-ID: CWE-416

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 fs/quota/quota_tree.c does not validate the block number in the quota tree (on disk). A local user can trigger use-after-free error and perform a denial-of-service attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: 5.15.0 - 5.15.2

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External links
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.3
https://www.openwall.com/lists/oss-security/2022/03/17/2
https://www.openwall.com/lists/oss-security/2022/03/17/1
https://bugzilla.kernel.org/show_bug.cgi?id=214655
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9bf3d20331295b1ecb81f4ed9ef358c51699a050
https://security.netapp.com/advisory/ntap-20220419-0003/

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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.