How severe is CVE-2021-42759?

CVE-2021-42759 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-42759 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-42759?

CVE-2021-42759 affects Fortinet Meru Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-42759?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-42759 published?

CVE-2021-42759 was published on 2021-12-09 and last updated on 2026-06-17.

CVE-2021-42759

CVE-2021-42759 is a medium-severity vulnerability in Fortinet Meru Firmware with a CVSS 3.x base score of 6.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: Medium (CVSS 3.x base score 6.7)
CVSS v2: 7.2
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Fortinet Meru Firmware
Published: 2021-12-09
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-42759?: CVE-2021-42759 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-42759 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-42759?: CVE-2021-42759 affects Fortinet Meru Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-42759?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-42759 published?: CVE-2021-42759 was published on 2021-12-09 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-004

Affected products (1)

cpe:2.3:o:fortinet:meru_firmware:*:*:*:*:*:*:*:*

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