How severe is CVE-2021-36187?

CVE-2021-36187 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2021-36187 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-36187?

CVE-2021-36187 primarily affects Fortinet Fortiweb. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-36187?

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

When was CVE-2021-36187 published?

CVE-2021-36187 was published on 2021-11-02 and last updated on 2026-06-17.

CVE-2021-36187

CVE-2021-36187 is a medium-severity vulnerability in Fortinet Fortiweb with a CVSS 3.x base score of 5.3. 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-400.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Fortinet Fortiweb
Published: 2021-11-02
Last modified: 2026-06-17

Description

A uncontrolled resource consumption in Fortinet FortiWeb version 6.4.0, version 6.3.15 and below, 6.2.5 and below allows attacker to cause a denial of service for webserver daemon via crafted HTTP requests

Frequently asked questions

What is CVE-2021-36187?: A uncontrolled resource consumption in Fortinet FortiWeb version 6.4.0, version 6.3.15 and below, 6.2.5 and below allows attacker to cause a denial of service for webserver daemon via crafted HTTP requests
How severe is CVE-2021-36187?: CVE-2021-36187 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2021-36187 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-36187?: CVE-2021-36187 primarily affects Fortinet Fortiweb. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-36187?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-36187 published?: CVE-2021-36187 was published on 2021-11-02 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-039

Affected products (2)

cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.4.0:*:*:*:*:*:*:*

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