CVE-2021-3959
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA Server-Side Request Forgery (SSRF) vulnerability exists in the EPPUpdateService component of Bitdefender Endpoint Security Tools. The flaw allows an attacker to make the vulnerable service proxy requests to an arbitrary relay server, potentially enabling internal network reconnaissance or bypassing network segmentation controls.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 3.3.8.272CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify GravityZone installation and versionLocate the Bitdefender GravityZone installation and retrieve the installed version number. This may be found in the control panel, installation directory, or management console.Affected if The installed version is lower than 3.3.8.272
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Confirm EPPUpdateService component statusVerify whether the EPPUpdateService component is present and enabled in the Bitdefender installation. Check the services console or GravityZone management interface for this component.Affected if EPPUpdateService is present and running, and the version is below 3.3.8.272
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Review network exposure of update serviceExamine firewall rules and network configuration to determine if the EPPUpdateService is accessible from network segments where it could receive malicious requests.Affected if EPPUpdateService is network-exposed and the version is below 3.3.8.272
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Inspect outbound connection logsReview network logs or proxy logs for unusual outbound connections originating from the Bitdefender update service to unexpected external addresses.Affected if Unexpected outbound connections are observed from the update service and the version is below 3.3.8.272
The environment is affected if Bitdefender GravityZone version is below 3.3.8.272 and the EPPUpdateService component is enabled and accessible.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped3.3.8.272
Upgrade Bitdefender GravityZone to version 3.3.8.272 or later. Until the patch is applied, restrict network access to the EPPUpdateService and monitor for unusual outbound connections.
GravityZone version 3.3.8.272 or later
- Check the current installed version of Bitdefender GravityZone
- Upgrade GravityZone to version 3.3.8.272 or later
- Verify the upgrade was successful by confirming the new version number in the management console
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3959 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-3959 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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