What is CVE-2020-36557?

CVE-2020-36557 is a medium-severity vulnerability in Linux Kernel, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.1/10. Published 2022-07-21.

How severe is CVE-2020-36557?

Medium severity. CVSS v3 base score is 5.1 out of 10.

Use After Free in Linux Kernel

CVE-2020-36557

A race condition in the Linux kernel before 5.6.2 between the VT_DISALLOCATE ioctl and closing/opening of ttys could lead to a use-after-free.

Vulnerability class: Race Condition

Published 2022-07-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.1 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.002 (9.1th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 9.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Linux Kernel

Weakness classification (CWE)

References

git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ (Patch, Mailing List, Vendor Advisory)
cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.6.2 (Patch, Release Notes, Vendor Advisory)

Frequently asked questions

What is CVE-2020-36557?: CVE-2020-36557 is a medium-severity vulnerability in Linux Kernel, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.1/10. Published 2022-07-21.
How severe is CVE-2020-36557?: Medium severity. CVSS v3 base score is 5.1 out of 10.