How severe is CVE-2021-43071?

CVE-2021-43071 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-43071 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43071?

CVE-2021-43071 primarily affects Fortinet Fortiweb. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43071?

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-2021-43071 published?

CVE-2021-43071 was published on 2021-12-09 and last updated on 2026-06-17.

CVE-2021-43071

CVE-2021-43071 is a high-severity vulnerability in Fortinet Fortiweb with a CVSS 3.x base score of 8.8. 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-787.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Fortinet Fortiweb
Published: 2021-12-09
Last modified: 2026-06-17

Description

A heap-based buffer overflow in Fortinet FortiWeb version 6.4.1 and 6.4.0, version 6.3.15 and below, version 6.2.6 and below allows attacker to execute unauthorized code or commands via crafted HTTP requests to the LogReport API controller.

Frequently asked questions

What is CVE-2021-43071?: A heap-based buffer overflow in Fortinet FortiWeb version 6.4.1 and 6.4.0, version 6.3.15 and below, version 6.2.6 and below allows attacker to execute unauthorized code or commands via crafted HTTP requests to the LogReport API controller.
How severe is CVE-2021-43071?: CVE-2021-43071 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-43071 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43071?: CVE-2021-43071 primarily affects Fortinet Fortiweb. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43071?: 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-2021-43071 published?: CVE-2021-43071 was published on 2021-12-09 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-188

Affected products (3)

cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.4.0:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortiweb:6.4.1:*:*:*:*:*:*:*

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