#VU90204 Use-after-free in Linux kernel - CVE-2021-47195

Vulnerability identifier: #VU90204

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-2021-47195

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 spi_unregister_controller() function in drivers/spi/spi.c. A local user can escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 5.4, 5.4.0, 5.4.0 rc6, 5.4.1, 5.4.2, 5.4.3, 5.4.4, 5.4.5, 5.4.6, 5.4.7, 5.4.8, 5.4.9, 5.4.10, 5.4.11, 5.4.12, 5.4.13, 5.4.14, 5.4.15, 5.4.16, 5.4.17, 5.4.18, 5.4.19, 5.4.20, 5.4.21, 5.4.22, 5.4.23, 5.4.24, 5.4.25, 5.4.26, 5.4.27, 5.4.28, 5.4.29, 5.4.30, 5.4.31, 5.4.32, 5.4.33, 5.4.34, 5.4.35, 5.4.36, 5.4.37, 5.4.38, 5.4.39, 5.4.40, 5.4.41, 5.4.42, 5.4.43, 5.4.44, 5.4.45, 5.4.46, 5.4.47, 5.4.48, 5.4.49, 5.4.50, 5.4.51, 5.4.52, 5.4.53, 5.4.54, 5.4.55, 5.4.56, 5.4.57, 5.4.58, 5.4.59, 5.4.60, 5.4.61, 5.4.62, 5.4.63, 5.4.64, 5.4.65, 5.4.66, 5.4.67, 5.4.68, 5.4.69, 5.4.70, 5.4.71, 5.4.72, 5.4.73, 5.4.74, 5.4.75, 5.4.76, 5.4.77, 5.4.78, 5.4.79, 5.4.80, 5.4.81, 5.4.82, 5.4.83, 5.4.84, 5.4.85, 5.4.86, 5.4.87, 5.4.88, 5.4.89, 5.4.90, 5.4.91, 5.4.92, 5.4.93, 5.4.94, 5.4.95, 5.4.96, 5.4.97, 5.4.98, 5.4.99, 5.4.100, 5.4.101, 5.4.102, 5.4.103, 5.4.104, 5.4.105, 5.4.106, 5.4.107, 5.4.108, 5.4.109, 5.4.110, 5.4.111, 5.4.112, 5.4.113, 5.4.114, 5.4.115, 5.4.116, 5.4.117, 5.4.118, 5.4.119, 5.4.120, 5.4.121, 5.4.122, 5.4.123, 5.4.124, 5.4.125, 5.4.126, 5.4.127, 5.4.128, 5.4.129, 5.4.130, 5.4.131, 5.4.132, 5.4.133, 5.4.134, 5.4.135, 5.4.136, 5.4.137, 5.4.138, 5.4.139, 5.4.140, 5.4.141, 5.4.142, 5.4.143, 5.4.144, 5.4.145, 5.4.146, 5.4.147, 5.4.148, 5.4.149, 5.4.150, 5.4.151, 5.4.152, 5.4.153, 5.4.154, 5.4.155, 5.4.156, 5.4.157, 5.4.158, 5.4.159, 5.4.160, 5.4.161, 5.4.162, 5.4.163, 5.4.164, 5.4.165, 5.4.166, 5.4.167, 5.4.168, 5.4.169, 5.4.170, 5.4.171, 5.4.172, 5.4.173, 5.4.174, 5.4.175, 5.4.176, 5.4.177, 5.4.178, 5.4.179, 5.4.180, 5.4.181, 5.4.182, 5.4.183, 5.4.184, 5.4.185, 5.4.186, 5.4.187, 5.4.188, 5.4.189, 5.4.190, 5.4.191, 5.4.192, 5.4.193, 5.4.194, 5.4.195, 5.4.196, 5.4.197, 5.4.198, 5.4.199, 5.4.200, 5.4.201, 5.4.202, 5.4.203, 5.4.204, 5.4.205, 5.4.206, 5.4.207, 5.4.208, 5.4.209, 5.4.210, 5.4.211, 5.4.212, 5.4.213, 5.4.214, 5.4.215, 5.4.216, 5.4.217, 5.4.218, 5.4.219, 5.4.220, 5.4.221, 5.4.222, 5.4.223, 5.4.224, 5.4.225, 5.4.226, 5.4.227, 5.4.228, 5.4.229, 5.4.230, 5.4.231, 5.4.232, 5.4.233, 5.4.234, 5.4.235, 5.4.236, 5.4.237, 5.4.238, 5.4.239, 5.4.240, 5.4.241, 5.4.242, 5.4.243, 5.4.244, 5.4.245, 5.4.246, 5.4.247, 5.4.248, 5.4.249, 5.4.250, 5.4.251, 5.4.252, 5.4.253, 5.4.254, 5.4.255, 5.4.256, 5.4.257, 5.4.258, 5.4.259, 5.4.260, 5.4.261, 5.4.262, 5.4.263, 5.4.264, 5.4.265, 5.4.266, 5.4.267, 5.4.268, 5.4.269, 5.4.270, 5.4.271, 5.4.272, 5.4.273, 5.4.274, 5.4.275, 5.4.276, 5.4.277, 5.4.278, 5.4.279, 5.4.280, 5.4.281, 5.4.282, 5.4.283, 5.4.284, 5.4.285, 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, 5.10.37, 5.10.38, 5.10.39, 5.10.40, 5.10.41, 5.10.42, 5.10.43, 5.10.44, 5.10.45, 5.10.46, 5.10.47, 5.10.48, 5.10.49, 5.10.50, 5.10.51, 5.10.52, 5.10.53, 5.10.54, 5.10.55, 5.10.56, 5.10.57, 5.10.58, 5.10.59, 5.10.60, 5.10.61, 5.10.62, 5.10.63, 5.10.64, 5.10.65, 5.10.66, 5.10.67, 5.10.68, 5.10.69, 5.10.70, 5.10.71, 5.10.72, 5.10.73, 5.10.74, 5.10.75, 5.10.76, 5.10.77, 5.10.78, 5.10.79, 5.10.80, 5.10.81, 5.10.82, 5.10.83, 5.10.84, 5.10.85, 5.10.86, 5.10.87, 5.10.88, 5.10.89, 5.10.90, 5.10.91, 5.10.92, 5.10.93, 5.10.94, 5.10.95, 5.10.96, 5.10.97, 5.10.98, 5.10.99, 5.10.100, 5.10.101, 5.10.102, 5.10.103, 5.10.104, 5.10.105, 5.10.106, 5.10.107, 5.10.108, 5.10.109, 5.10.110, 5.10.111, 5.10.112, 5.10.113, 5.10.114, 5.10.115, 5.10.116, 5.10.117, 5.10.118, 5.10.119, 5.10.120, 5.10.121, 5.10.122, 5.10.123, 5.10.124, 5.10.125, 5.10.126, 5.10.127, 5.10.128, 5.10.129, 5.10.130, 5.10.131, 5.10.132, 5.10.133, 5.10.134, 5.10.135, 5.10.136, 5.10.137, 5.10.138, 5.10.139, 5.10.140, 5.10.141, 5.10.142, 5.10.143, 5.10.144, 5.10.145, 5.10.146, 5.10.147, 5.10.148, 5.10.149, 5.10.150, 5.10.151, 5.10.152, 5.10.153, 5.10.154, 5.10.155, 5.10.156, 5.10.157, 5.10.158, 5.10.159, 5.10.160, 5.10.161, 5.10.162, 5.10.163, 5.10.164, 5.10.165, 5.10.166, 5.10.167, 5.10.168, 5.10.169, 5.10.170, 5.10.171, 5.10.172, 5.10.173, 5.10.174, 5.10.175, 5.10.176, 5.10.177, 5.10.178, 5.10.179, 5.10.180, 5.10.181, 5.10.182, 5.10.183, 5.10.184, 5.10.185, 5.10.186, 5.10.187, 5.10.188, 5.10.189, 5.10.190, 5.10.191, 5.10.192, 5.10.193, 5.10.194, 5.10.195, 5.10.196, 5.10.197, 5.10.198, 5.10.199, 5.10.200, 5.10.201, 5.10.202, 5.10.203, 5.10.204, 5.10.205, 5.10.206, 5.10.207, 5.10.208, 5.10.209, 5.10.210, 5.10.211, 5.10.212, 5.10.213, 5.10.214, 5.10.215, 5.10.216, 5.10.217, 5.10.218, 5.10.219, 5.10.220, 5.10.221, 5.10.222, 5.10.223, 5.10.224, 5.10.225, 5.10.226, 5.10.227, 5.10.228, 5.10.229, 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, 5.16 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/37330f37f6666c7739a44b2b6b95b047ccdbed2d
https://git.kernel.org/stable/c/6c53b45c71b4920b5e62f0ea8079a1da382b9434
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.230
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.5
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.16
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.286

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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.