CVE-2018-5736
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 error in zone database reference counting can lead to an assertion failure if a server which is running an affected version of BIND attempts several transfers of a slave zone in quick succession. This defect could be deliberately exercised by an attacker who is permitted to cause a vulnerable server to initiate zone transfers (for example: by sending valid NOTIFY messages), causing the named process to exit after failing the assertion test. Affects BIND 9.12.0 and 9.12.1.
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 confidenceA reference counting error in the zone database of BIND 9.12.0 and 9.12.1 causes an assertion failure during rapid slave zone transfers. An attacker with the ability to trigger zone transfers (e.g., via valid NOTIFY messages) can cause the named process to crash, resulting in denial of service.
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= 9.12.0= 9.12.1all versionsall versionsCVSS 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
- High
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:H/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 BIND versionRun 'named -v' or 'named -V' to display the installed BIND versionAffected if The version shown is 9.12.0 or 9.12.1
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Check if BIND operates as a slaveReview named.conf or zone configuration files for 'type slave' or 'type secondary' zone definitionsAffected if Any zone is configured as a slave/secondary receiving transfers from masters
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Verify NOTIFY handling is enabledCheck named.conf for 'notify' directive set to 'yes' (default) and examine any 'allow-notify' ACLsAffected if NOTIFY processing is enabled, which allows external hosts to trigger zone transfers
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Confirm slave zone transfer capabilityLook for 'allow-transfer' or 'also-notify' statements in zone or options blocks that permit zone transfersAffected if The server is configured to accept zone transfers from untrusted or broad sets of hosts
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Check NetApp product integrationFor NetApp Cloud Backup or Data Ontap Edge, identify the embedded BIND version if accessible, or confirm the product uses BIND 9.12.0-9.12.1Affected if The product bundles or depends on the vulnerable BIND version
The environment is affected if running BIND version 9.12.0 or 9.12.1 with slave zone configurations that accept NOTIFY messages or zone transfers from potentially untrusted sources.
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 BIND to version 9.12.2 or later where the reference counting bug is fixed. Additionally, restrict which hosts can send NOTIFY messages using ACLs to limit attack surface.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-5736 — 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-2018-5736 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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- Version or environment caveats, and links to real fixes
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