Privilege escalation in tty subsystem in Linux kernel

Published: 2020-12-09 | Updated: 2021-03-17
Risk Low
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-29661
Exploitation vector Local
Public exploit N/A
Vulnerable software
Linux kernel
Operating systems & Components / Operating system


Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Improper locking

EUVDB-ID: #VU51543

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-29661

CWE-ID: CWE-667 - Improper Locking

Exploit availability: No


The vulnerability allows a local user to perform a escalate privileges on the system.

The vulnerability exists due to locking error in the tty subsystem of the Linux kernel in drivers/tty/tty_jobctrl.c. An local user can exploit this vulnerability to trigger a use-after-free error against TIOCSPGRP and execute arbitrary code with elevated privileges.


Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.9.14

CPE2.3 External links

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.