Privilege escalation in Linux kernel JSIOCSBTNMAP IOCTL

1) Out-of-bounds write

EUVDB-ID: #VU55231

Risk: Low

CVSSv3.1: 6.1 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-3612

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error in joystick devices subsystem in Linux kernel. A local user can make a specially crafted JSIOCSBTNMAP IOCTL call, trigger out-of-bounds write and execute arbitrary code with escalated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.9 rc1

External links

http://lore.kernel.org/linux-input/20210620120030.1513655-1-avlarkin82@gmail.com/
http://bugzilla.redhat.com/show_bug.cgi?id=1974079

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.