How severe is CVE-2021-33600?

CVE-2021-33600 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-33600 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33600?

CVE-2021-33600 affects F-secure Internet Gatekeeper. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33600?

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

When was CVE-2021-33600 published?

CVE-2021-33600 was published on 2021-09-28 and last updated on 2026-06-17.

CVE-2021-33600

CVE-2021-33600 is a medium-severity vulnerability in F-secure Internet Gatekeeper with a CVSS 3.x base score of 5.4. 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-617.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 5.0
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-617
Affected product: F-secure Internet Gatekeeper
Published: 2021-09-28
Last modified: 2026-06-17

Description

A denial-of-service (DoS) vulnerability was discovered in the web user interface of F-Secure Internet Gatekeeper. The vulnerability occurs because of an attacker can trigger assertion via malformed HTTP packet to web interface. An unauthenticated attacker could exploit this vulnerability by sending a large username parameter. A successful exploitation could lead to a denial-of-service of the product.

Frequently asked questions

What is CVE-2021-33600?: A denial-of-service (DoS) vulnerability was discovered in the web user interface of F-Secure Internet Gatekeeper. The vulnerability occurs because of an attacker can trigger assertion via malformed HTTP packet to web interface. An unauthenticated attacker could exploit this vulnerability by sending a large username parameter. A successful exploitation could lead to a denial-of-service of the product.
How severe is CVE-2021-33600?: CVE-2021-33600 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-33600 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33600?: CVE-2021-33600 affects F-secure Internet Gatekeeper. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33600?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-33600 published?: CVE-2021-33600 was published on 2021-09-28 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:f-secure:internet_gatekeeper:*:*:*:*:*:*:*:*

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