How severe is CVE-2021-3959?

CVE-2021-3959 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-3959 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3959?

CVE-2021-3959 affects Bitdefender Gravityzone. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3959?

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

When was CVE-2021-3959 published?

CVE-2021-3959 was published on 2021-12-16 and last updated on 2026-06-17.

CVE-2021-3959

CVE-2021-3959 is a medium-severity vulnerability in Bitdefender Gravityzone with a CVSS 3.x base score of 6.8. 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-918.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 5.0
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-918
Affected product: Bitdefender Gravityzone
Published: 2021-12-16
Last modified: 2026-06-17

Description

A Server-Side Request Forgery (SSRF) vulnerability in the EPPUpdateService component of Bitdefender Endpoint Security Tools allows an attacker to proxy requests to the relay server. This issue affects: Bitdefender Bitdefender GravityZone versions prior to 3.3.8.272

Frequently asked questions

What is CVE-2021-3959?: A Server-Side Request Forgery (SSRF) vulnerability in the EPPUpdateService component of Bitdefender Endpoint Security Tools allows an attacker to proxy requests to the relay server. This issue affects: Bitdefender Bitdefender GravityZone versions prior to 3.3.8.272
How severe is CVE-2021-3959?: CVE-2021-3959 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-3959 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3959?: CVE-2021-3959 affects Bitdefender Gravityzone. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3959?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-3959 published?: CVE-2021-3959 was published on 2021-12-16 and last updated on 2026-06-17.

References

https://www.bitdefender.com/support/security-advisories/server-side-request-forgery-in-bitdefender-gravityzone-update-server-in-relay-mode-va-10145

Affected products (1)

cpe:2.3:a:bitdefender:gravityzone:*:*:*:*:*:*:*:*

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