#VU81693 Use-after-free in Linux kernel - CVE-2023-4921

Vulnerability identifier: #VU81693

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2023-4921

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 escalate privileges on the system.

The vulnerability exists due to a use-after-free error in the qfq_dequeue() function within the the Linux kernel's net/sched: sch_qfq component. A local user can trigger a use-after-free error and execute arbitrary code with elevated privileges.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: before 6.6, 6.6

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External links
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8fc134fee27f2263988ae38920bc03da416b03d8
https://kernel.dance/8fc134fee27f2263988ae38920bc03da416b03d8

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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.