#VU83433 Use-after-free in Linux kernel - CVE-2021-3348

Vulnerability identifier: #VU83433

Vulnerability risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3348

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 authenticated user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the nbd_add_socket in drivers/block/nbd.c. A local authenticated user can trigger a use-after-free error and escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: before 5.10.13, 5.10.13

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External links
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b98e762e3d71e893b221f871825dc64694cfb258
https://www.openwall.com/lists/oss-security/2021/01/28/3
https://www.openwall.com/lists/oss-security/2021/02/01/1
https://lists.debian.org/debian-lts-announce/2021/03/msg00035.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.