#VU90223 Use-after-free in Linux kernel - CVE-2021-47131
Vulnerability identifier: #VU90223
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-2021-47131
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 tls_ctx_create() function in net/tls/tls_main.c, within the tls_validate_xmit_skb() function in net/tls/tls_device_fallback.c, within the tls_device_gc_task(), tls_device_rx_resync_new_rec(), tls_device_decrypted() and tls_device_down() functions in net/tls/tls_device.c. A local user can escalate privileges on the system.
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, 5.10.37, 5.10.38, 5.10.39, 5.10.40, 5.10.41, 5.10.42, 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, 5.12.5, 5.12.6, 5.12.7, 5.12.8, 5.12.9, 5.13 rc1, 5.13 rc4, 5.13 rc5
External links
https://git.kernel.org/stable/c/f1d4184f128dede82a59a841658ed40d4e6d3aa2
https://git.kernel.org/stable/c/0f1e6fe66977a864fe850522316f713d7b926fd9
https://git.kernel.org/stable/c/c55dcdd435aa6c6ad6ccac0a4c636d010ee367a4
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.43
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.10
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13
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.
