Debian LinuxOperating system · Debian
CVE-2016-2120
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 · uneditedAn issue has been found in PowerDNS Authoritative Server versions up to and including 3.4.10, 4.0.1 allowing an authorized user to crash the server by inserting a specially crafted record in a zone under their control then sending a DNS query for that record. The issue is due to an integer overflow when checking if the content of the record matches the expected size, allowing an attacker to cause a read past the buffer boundary.
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 · moderate confidenceInteger overflow vulnerability in PowerDNS Authoritative Server versions up to 3.4.10 and 4.0.1 allows an authorized user to crash the server by inserting specially crafted DNS records in a zone they control, then querying for those records. The flaw occurs during record content size validation, causing an out-of-bounds read past the buffer boundary.
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
Debian LinuxOperating system
= 8.0<= 3.4.10>= 4.0.0, <= 4.0.1CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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 PowerDNS Authoritative Server installationRun 'pdns_server --version' or check the package manager (dpkg -l | grep pdns) on Debian systemsAffected if PowerDNS Authoritative Server is not installed
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Determine installed versionExecute 'pdns_server --version' to retrieve the version number, or use 'dpkg -l | grep pdns-auth' on DebianAffected if Version is 3.4.10 or earlier, or between 4.0.0 and 4.0.1 inclusive
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Confirm the server is runningRun 'pdns_control ping' or query the server with 'dig @localhost SOA <zonename>' to verify it is operationalAffected if Server is not running (vulnerability cannot be triggered)
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Check if untrusted users can add records to zonesReview pdns.conf for zone transfer and update ACLs, or check zone metadata to determine if users without full administrative privileges can insert DNS recordsAffected if Users who are not fully trusted administrators have the ability to insert DNS records into zones they control
System is affected if PowerDNS Authoritative Server version is 3.4.10 or earlier, or between 4.0.0 and 4.0.1, the server is running, and untrusted users can insert crafted DNS records into zones they control and then query for those records.
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 PowerDNS Authoritative Server to version 4.0.2 or later, which contains the fix for this integer overflow vulnerability.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-2120 — 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-2016-2120 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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