#VU90251 Use-after-free in Linux kernel - CVE-2021-46991

Vulnerability identifier: #VU90251

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-2021-46991

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 i40e_client_subtask() function in drivers/net/ethernet/intel/i40e/i40e_client.c. A local user can escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 4.19, 4.19.1, 4.19.2, 4.19.3, 4.19.4, 4.19.5, 4.19.6, 4.19.7, 4.19.8, 4.19.9, 4.19.10, 4.19.11, 4.19.12, 4.19.13, 4.19.14, 4.19.15, 4.19.16, 4.19.17, 4.19.18, 4.19.19, 4.19.20, 4.19.21, 4.19.22, 4.19.23, 4.19.24, 4.19.25, 4.19.26, 4.19.27, 4.19.28, 4.19.29, 4.19.30, 4.19.31, 4.19.32, 4.19.33, 4.19.34, 4.19.35, 4.19.36, 4.19.37, 4.19.38, 4.19.39, 4.19.40, 4.19.41, 4.19.42, 4.19.43, 4.19.44, 4.19.45, 4.19.46, 4.19.47, 4.19.48, 4.19.49, 4.19.50, 4.19.51, 4.19.52, 4.19.53, 4.19.54, 4.19.55, 4.19.56, 4.19.57, 4.19.58, 4.19.59, 4.19.60, 4.19.61, 4.19.62, 4.19.63, 4.19.64, 4.19.65, 4.19.66, 4.19.67, 4.19.68, 4.19.69, 4.19.70, 4.19.71, 4.19.72, 4.19.73, 4.19.74, 4.19.75, 4.19.76, 4.19.77, 4.19.78, 4.19.79, 4.19.80, 4.19.81, 4.19.82, 4.19.83, 4.19.84, 4.19.85, 4.19.86, 4.19.87, 4.19.88, 4.19.89, 4.19.90, 4.19.91, 4.19.92, 4.19.93, 4.19.94, 4.19.95, 4.19.96, 4.19.97, 4.19.98, 4.19.99, 4.19.100, 4.19.101, 4.19.102, 4.19.103, 4.19.104, 4.19.105, 4.19.106, 4.19.107, 4.19.108, 4.19.109, 4.19.110, 4.19.111, 4.19.112, 4.19.113, 4.19.114, 4.19.115, 4.19.116, 4.19.117, 4.19.118, 4.19.118-2, 4.19.119, 4.19.120, 4.19.121, 4.19.122, 4.19.123, 4.19.124, 4.19.125, 4.19.126, 4.19.127, 4.19.128, 4.19.129, 4.19.130, 4.19.131, 4.19.132, 4.19.133, 4.19.134, 4.19.135, 4.19.136, 4.19.137, 4.19.138, 4.19.139, 4.19.140, 4.19.141, 4.19.142, 4.19.143, 4.19.144, 4.19.145, 4.19.146, 4.19.147, 4.19.148, 4.19.149, 4.19.150, 4.19.151, 4.19.152, 4.19.153, 4.19.154, 4.19.155, 4.19.156, 4.19.157, 4.19.158, 4.19.159, 4.19.160, 4.19.161, 4.19.162, 4.19.163, 4.19.164, 4.19.165, 4.19.166, 4.19.167, 4.19.168, 4.19.169, 4.19.170, 4.19.171, 4.19.172, 4.19.173, 4.19.174, 4.19.175, 4.19.176, 4.19.177, 4.19.178, 4.19.179, 4.19.180, 4.19.181, 4.19.182, 4.19.183, 4.19.184, 4.19.185, 4.19.186, 4.19.187, 4.19.188, 4.19.189, 4.19.190, 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, 5.10, 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, 5.11, 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, 5.11.21, 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, 5.12.4, 5.13 rc1, 5.13 rc4, 5.13 rc5

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External links
https://git.kernel.org/stable/c/c1322eaeb8af0d8985b5cc5fa759140fa0e57b84
https://git.kernel.org/stable/c/d718c15a2bf9ae082d5ae4d177fb19ef23cb4132
https://git.kernel.org/stable/c/829a713450b8fb127cbabfc1244c1d8179ec5107
https://git.kernel.org/stable/c/4ebc10aa7cd17fd9857dedac69600465c9dd16d1
https://git.kernel.org/stable/c/1fd5d262e7442192ac7611ff1597a36c5b044323
https://git.kernel.org/stable/c/38318f23a7ef86a8b1862e5e8078c4de121960c3
https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.191
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.38
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.22
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.5
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.120

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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.