#VU90806 Improper locking in Linux kernel - CVE-2021-47038

Vulnerability identifier: #VU90806

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-2021-47038

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 hci_conn_get_phy() function in net/bluetooth/hci_conn.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 5.10, 5.10 rc1, 5.10 rc2, 5.10 rc3, 5.10 rc4, 5.10 rc5, 5.10 rc7, 5.10.1, 5.10.2, 5.10.3, 5.10.4, 5.10.5, 5.10.6, 5.10.7, 5.10.8, 5.10.9, 5.10.10, 5.10.11, 5.10.12, 5.10.13, 5.10.14, 5.10.15, 5.10.16, 5.10.17, 5.10.18, 5.10.19, 5.10.20, 5.10.21, 5.10.22, 5.10.23, 5.10.24, 5.10.25, 5.10.26, 5.10.27, 5.10.28, 5.10.29, 5.10.30, 5.10.31, 5.10.32, 5.10.33, 5.10.34, 5.10.35, 5.10.36, 5.11, 5.11 rc1, 5.11.1, 5.11.2, 5.11.3, 5.11.4, 5.11.5, 5.11.6, 5.11.7, 5.11.8, 5.11.9, 5.11.10, 5.11.11, 5.11.12, 5.11.13, 5.11.14, 5.11.15, 5.11.16, 5.11.17, 5.11.18, 5.11.19, 5.11.20, 5.12, 5.12 rc1, 5.12 rc2, 5.12 rc3, 5.12 rc4, 5.12 rc6, 5.12 rc8, 5.12.1, 5.12.2, 5.12.3, 5.13 rc1, 5.13 rc4, 5.13 rc5

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External links
https://git.kernel.org/stable/c/7cc0ba67883c6c8d3bddb283f56c167fc837a555
https://git.kernel.org/stable/c/fee71f480bc1dec5f6ae3b0b185ff12a62bceabc
https://git.kernel.org/stable/c/332e69eb3bd90370f2d9f2c2ca7974ff523dea17
https://git.kernel.org/stable/c/17486960d79b900c45e0bb8fbcac0262848582ba
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.37
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.21
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13

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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.