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Endpoint Security ToolsApplication · Bitdefender

CVE-2021-3553

HIGH · 7.5 CVSS v3.1 Published 2021-11-24
Fix available
A fix is available. Upgrade to 6.2.21.160 / 6.6.27.390 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A Server-Side Request Forgery (SSRF) vulnerability in the EPPUpdateService of Bitdefender Endpoint Security Tools allows an attacker to use the Endpoint Protection relay as a proxy for any remote host. This issue affects: Bitdefender Endpoint Security Tools versions prior to 6.6.27.390; versions prior to 7.1.2.33. Bitdefender Unified Endpoint for Linux versions prior to 6.2.21.160. Bitdefender GravityZone versions prior to 6.24.1-1.

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 confidence

An SSRF vulnerability exists in the EPPUpdateService of Bitdefender Endpoint Security Tools, allowing attackers to abuse the Endpoint Protection relay as a proxy to make requests to arbitrary remote hosts. The service lacks proper validation of user-supplied URLs, enabling network-based attacks and potential internal network reconnaissance.

MitigationUpgrade to fixed versions of affected Bitdefender products (6.6.27.390 or 7.1.2.33 for Endpoint Security Tools, 6.2.21.160 for Unified Endpoint for Linux, 6.24.1-1 for GravityZone) to patch the vulnerable EPPUpdateService component.

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
Endpoint Security ToolsApplication
Affected:< 6.2.21.160>= 6.6.27.0, < 6.6.27.390>= 7.0.0.00, < 7.1.2.33
GravityzoneApplication
Affected:= 6.24.1-1

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify Bitdefender Endpoint Security Tools installation
    Check for Bitdefender Endpoint Security Tools processes or services running on the system, or look for Bitdefender installation directories
    Affected if The product is installed and running on the endpoint
  2. Identify installed product version
    Use the product's built-in version check mechanism, About dialog, or registry/command-line query to obtain the exact installed version number
    Affected if The version falls within < 6.2.21.160; >= 6.6.27.0 and < 6.6.27.390; or >= 7.0.0.00 and < 7.1.2.33
  3. Check for Bitdefender GravityZone version
    If using GravityZone console or agents, verify the GravityZone version number
    Affected if The GravityZone version equals 6.24.1-1
  4. Confirm EPPUpdateService is present and enabled
    Check if the EPPUpdateService Windows service or Linux daemon is installed and enabled on the endpoint
    Affected if The EPPUpdateService component is present and operational on the system

The environment is affected if Bitdefender Endpoint Security Tools or GravityZone is installed with a version matching the affected ranges and the EPPUpdateService component is active.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 6.2.21.160 / 6.6.27.390 / 7.1.2.33 or later
Fixed in 6.2.21.1606.6.27.3907.1.2.33
Interim mitigation

Upgrade to fixed versions of affected Bitdefender products (6.6.27.390 or 7.1.2.33 for Endpoint Security Tools, 6.2.21.160 for Unified Endpoint for Linux, 6.24.1-1 for GravityZone) to patch the vulnerable EPPUpdateService component.

Recommended fix High confidence

Endpoint Security Tools: 6.6.27.390, 7.1.2.33, or 6.2.21.160 (Linux) | GravityZone: 6.24.1-1

  1. 1. Identify the currently installed Bitdefender product (Endpoint Security Tools for Windows/Linux or GravityZone) and its exact version number
  2. 2. For Endpoint Security Tools: If running version < 6.2.21.160 (Linux), upgrade to 6.2.21.160 or later
  3. 3. For Endpoint Security Tools: If running version >= 6.6.27.0 and < 6.6.27.390, upgrade to version 6.6.27.390 or later
  4. 4. For Endpoint Security Tools: If running version >= 7.0.0.00 and < 7.1.2.33, upgrade to version 7.1.2.33 or later
  5. 5. For GravityZone: If running version 6.24.1-1 or prior, upgrade to version 6.24.1-1 (or latest stable release)
  6. 6. Verify the upgrade was successful by checking the product version in the Bitdefender management console
  7. 7. Confirm the EPPUpdateService has been patched and SSRF vulnerability is remediated
Caveat Review Bitdefender compatibility guides before upgrading; ensure system meets hardware/software requirements for the target version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Endpoint Security Tools Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-3553 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data