How severe is CVE-2021-36190?

CVE-2021-36190 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2021-36190 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-36190?

CVE-2021-36190 primarily affects Fortinet Fortiweb. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-36190?

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

When was CVE-2021-36190 published?

CVE-2021-36190 was published on 2021-12-08 and last updated on 2026-06-17.

CVE-2021-36190

CVE-2021-36190 is a medium-severity vulnerability in Fortinet Fortiweb with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 6.5
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Fortinet Fortiweb
Published: 2021-12-08
Last modified: 2026-06-17

Description

A unintended proxy or intermediary ('confused deputy') in Fortinet FortiWeb version 6.4.1 and below, 6.3.15 and below allows an unauthenticated attacker to access protected hosts via crafted HTTP requests.

Frequently asked questions

What is CVE-2021-36190?: A unintended proxy or intermediary ('confused deputy') in Fortinet FortiWeb version 6.4.1 and below, 6.3.15 and below allows an unauthenticated attacker to access protected hosts via crafted HTTP requests.
How severe is CVE-2021-36190?: CVE-2021-36190 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2021-36190 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-36190?: CVE-2021-36190 primarily affects Fortinet Fortiweb. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-36190?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-36190 published?: CVE-2021-36190 was published on 2021-12-08 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-123

Affected products (6)

cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.1.0:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.1.1:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.1.2:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.4.0:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.4.1:*:*:*:*:*:*:*

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