#VU92357 Improper locking in Linux kernel - CVE-2021-47615

Vulnerability identifier: #VU92357

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-2021-47615

CWE-ID: CWE-667

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 (DoS) attack.

The vulnerability exists due to improper locking within the mlx5_ib_dereg_mr(), mlx5_ib_alloc_pi_mr() and __mlx5_ib_alloc_mr() functions in drivers/infiniband/hw/mlx5/mr.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 5.15, 5.15 rc1, 5.15 rc2, 5.15 rc3, 5.15 rc4, 5.15 rc5, 5.15 rc6, 5.15 rc7, 5.15.0, 5.15.1, 5.15.2, 5.15.3, 5.15.4, 5.15.5, 5.15.6, 5.15.7, 5.15.8, 5.15.9, 5.15.11, 5.15.12, 5.15.13, 5.16 rc1, 5.16 rc2, 5.16 rc3, 5.16 rc4, 5.16 rc5, 5.16 rc6, 5.16 rc8

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External links
https://git.kernel.org/stable/c/e3bc4d4b50cae7db08e50dbe43f771c906e97701
https://git.kernel.org/stable/c/c44979ace49b4aede3cc7cb5542316e53a4005c9
https://git.kernel.org/stable/c/f0ae4afe3d35e67db042c58a52909e06262b740f
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.10
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.14
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.16

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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.