What is CVE-2020-20267?

CVE-2020-20267 is a medium-severity vulnerability in Mikrotik Routeros, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2021-05-11.

How severe is CVE-2020-20267?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Buffer overflow in Mikrotik Routeros

CVE-2020-20267

Mikrotik RouterOs before 6.47 (stable tree) suffers from a memory corruption vulnerability in the /nova/bin/resolver process. An authenticated remote attacker can cause a Denial of Service due to invalid memory access.

Vulnerability class: Buffer Overflow

Published 2021-05-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.017 (76.5th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 76.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.017 · newest: 0.017 · change: 0.000

Affected products

Mikrotik Routeros

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

seclists.org/fulldisclosure/2021/May/12 (Exploit, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2020-20267?: CVE-2020-20267 is a medium-severity vulnerability in Mikrotik Routeros, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2021-05-11.
How severe is CVE-2020-20267?: Medium severity. CVSS v3 base score is 6.5 out of 10.