What is CVE-2021-42759?

CVE-2021-42759 is a medium-severity vulnerability in Fortinet Meru Ap, classified under OS Command Injection. CVSS score: 6.7/10. Published 2021-12-09.

How severe is CVE-2021-42759?

Medium severity. CVSS v3 base score is 6.7 out of 10.

RCE in Fortinet Meru Ap

CVE-2021-42759

A violation of secure design principles in Fortinet Meru AP version 8.6.1 and below, version 8.5.5 and below allows attacker to execute unauthorized code or commands via crafted cli commands.

Vulnerability class: Command Injection (OS Command Injection)

Published 2021-12-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (16.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Fortinet Meru Ap — versions Meru AP 8.6.1, 8.6.0, 8.5.5, 8.5.4, 8.5.3, 8.5.2, 8.5.1, 8.5.0
Fortinet Meru
Fortinet Meru Firmware

Weakness classification (CWE)

CWE-78 — OS Command Injection

References

fortiguard.com/advisory/FG-IR-21-004 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-42759?: CVE-2021-42759 is a medium-severity vulnerability in Fortinet Meru Ap, classified under OS Command Injection. CVSS score: 6.7/10. Published 2021-12-09.
How severe is CVE-2021-42759?: Medium severity. CVSS v3 base score is 6.7 out of 10.