How severe is CVE-2021-22128?

CVE-2021-22128 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability high.

Is CVE-2021-22128 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-22128?

CVE-2021-22128 primarily affects Fortinet Fortiproxy. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-22128?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-22128 published?

CVE-2021-22128 was published on 2021-03-04 and last updated on 2026-06-17.

CVE-2021-22128

CVE-2021-22128 is a high-severity vulnerability in Fortinet Fortiproxy with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.1)
CVSS v2: 4.0
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Fortinet Fortiproxy
Published: 2021-03-04
Last modified: 2026-06-17

Description

An improper access control vulnerability in FortiProxy SSL VPN portal 2.0.0, 1.2.9 and below versions may allow an authenticated, remote attacker to access internal service such as the ZebOS Shell on the FortiProxy appliance through the Quick Connection functionality.

Frequently asked questions

What is CVE-2021-22128?: An improper access control vulnerability in FortiProxy SSL VPN portal 2.0.0, 1.2.9 and below versions may allow an authenticated, remote attacker to access internal service such as the ZebOS Shell on the FortiProxy appliance through the Quick Connection functionality.
How severe is CVE-2021-22128?: CVE-2021-22128 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability high.
Is CVE-2021-22128 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-22128?: CVE-2021-22128 primarily affects Fortinet Fortiproxy. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-22128?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-22128 published?: CVE-2021-22128 was published on 2021-03-04 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-20-235

Affected products (2)

cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiproxy:2.0.0:*:*:*:*:*:*:*

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