CVE-2020-8984
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 · uneditedlib/NSSDropbox.php in ZendTo prior to 5.22-2 Beta allowed IP address spoofing via the X-Forwarded-For header.
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 confidenceThe NSSDropbox.php library in ZendTo versions prior to 5.22-2 Beta improperly trusts the X-Forwarded-For HTTP header for IP address determination, allowing attackers to spoof their source IP address by manipulating this header. This can lead to bypass of IP-based access controls, rate limiting, or audit logging.
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= 3.10= 3.11= 3.12= 3.13= 3.20= 3.51= 3.52= 3.53= 3.54= 3.55= 3.56-2= 3.57CVSS 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
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 ZendTo installationLocate the ZendTo web application directory on your server. Check for the presence of the main ZendTo files such as index.php, config.php, or the NSSDropbox.php library file.Affected if ZendTo is installed and the NSSDropbox.php library is present in the codebase.
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Determine installed ZendTo versionCheck the version number of your ZendTo installation. This is typically found in a version file, the main configuration file, or displayed in the application admin interface under system information or about section. Compare your version against the affected range: 3.10, 3.11, 3.12, 3.13, 3.20, 3.51, 3.52, 3.53, 3.54, 3.55, 3.56-2, and 3.57.Affected if The installed version is any of the listed affected versions (3.10 through 3.57), or any version prior to 5.22-2 Beta.
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Inspect NSSDropbox.php for IP handling codeLocate the NSSDropbox.php file within your ZendTo installation. Examine the code that handles IP address determination, specifically looking for usage of the X-Forwarded-For HTTP header without proper validation or sanitization.Affected if The code uses $_SERVER['X-Forwarded-For'] or similar variables to determine client IP address without validating or filtering the header contents.
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Check IP determination configurationReview the ZendTo configuration files (such as config.php or any IP-related settings) to determine how the application handles IP address determination. Look for settings that enable trusting of X-Forwarded-For headers.Affected if The application is configured to trust or rely on X-Forwarded-For headers for IP-based access controls, rate limiting, or logging without additional validation.
You are affected if your ZendTo version is 3.10 through 3.57 (or any version prior to 5.22-2 Beta) AND the application trusts the X-Forwarded-For header for IP address determination.
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.
From vendor dataUpgrade to ZendTo 5.22-2 Beta or later. If immediate patching is not possible, configure the application to ignore X-Forwarded-For headers for IP determination or implement strict validation of forwarded IP addresses.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-8984 — 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-2020-8984 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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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.
- 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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