CVE-2020-36557

kernel: race condition between the VT_DISALLOCATE ioctl and closing/opening of ttys, causing a use-after-free in con_shutdown().

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Severity

Moderate

Red Hat Product Security

5.1

CVSS 3.1

Review impact separately from score.

Published · March 21, 2020

Updated · November 22, 2025

Description

A use-after-free flaw was found in the Linux kernel’s Virtual Terminal subsystem in how a user calls the VT_DISALLOCATE ioctl during the closing/opening of ttys. This flaw allows a local user to crash the system.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 5.1
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE-416 · Use After Free