How severe is CVE-2021-40833?

CVE-2021-40833 has a CVSS 3.x base score of 5.5, 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 low.

Is CVE-2021-40833 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40833?

CVE-2021-40833 primarily affects F-secure Atlant. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-40833?

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

When was CVE-2021-40833 published?

CVE-2021-40833 was published on 2021-11-26 and last updated on 2026-06-17.

CVE-2021-40833

CVE-2021-40833 is a medium-severity vulnerability in F-secure Atlant 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. The underlying weakness is classified as CWE-404.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 4.3
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-404
Affected product: F-secure Atlant
Published: 2021-11-26
Last modified: 2026-06-17

Description

A vulnerability affecting F-Secure antivirus engine was discovered whereby unpacking UPX file can lead to denial-of-service. The vulnerability can be exploited remotely by an attacker. A successful attack will result in denial-of-service of the antivirus engine.

Frequently asked questions

What is CVE-2021-40833?: A vulnerability affecting F-Secure antivirus engine was discovered whereby unpacking UPX file can lead to denial-of-service. The vulnerability can be exploited remotely by an attacker. A successful attack will result in denial-of-service of the antivirus engine.
How severe is CVE-2021-40833?: CVE-2021-40833 has a CVSS 3.x base score of 5.5, 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 low.
Is CVE-2021-40833 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40833?: CVE-2021-40833 primarily affects F-secure Atlant. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-40833?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-40833 published?: CVE-2021-40833 was published on 2021-11-26 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:f-secure:atlant:-:*:*:*:*:*:*:*
cpe:2.3:a:f-secure:internet_gatekeeper:-:*:*:*:*:*:*:*
cpe:2.3:a:f-secure:linux_security:-:*:*:*:*:*:x86:*
cpe:2.3:a:f-secure:linux_security_64:-:*:*:*:*:*:*:*
cpe:2.3:a:f-secure:elements_endpoint_protection:-:*:*:*:*:*:*:*

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