#VU104499 Use-after-free in Linux kernel - CVE-2021-47646

Vulnerability identifier: #VU104499

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-2021-47646

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 within the bfq_setup_merge() and bfq_setup_cooperator() functions in block/bfq-iosched.c. A local user can escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

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External links
https://git.kernel.org/stable/c/15729ff8143f8135b03988a100a19e66d7cb7ecd
https://git.kernel.org/stable/c/4083925bd6dc89216d156474a8076feec904e607
https://git.kernel.org/stable/c/65d8a737452e88f251fe5d925371de6d606df613
https://git.kernel.org/stable/c/931aff627469a75c77b9fd3823146d0575afffd6
https://git.kernel.org/stable/c/abc2129e646af7b43025d90a071f83043f1ae76c
https://git.kernel.org/stable/c/cc051f497eac9d8a0d816cd4bffa3415f2724871
https://git.kernel.org/stable/c/f990f0985eda59d4f29fc83fcf300c92b1225d39

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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.