CVE-2019-6469
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 the EDNS Client Subnet (ECS) feature for recursive resolvers can cause BIND to exit with an assertion failure when processing a response that has malformed RRSIGs. Versions affected: BIND 9.10.5-S1 -> 9.11.6-S1 of BIND 9 Supported Preview Edition.
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 vulnerability in BIND's EDNS Client Subnet (ECS) feature for recursive resolvers allows remote attackers to cause a denial of service. When processing a DNS response containing malformed RRSIG (Resource Record Signature) records, BIND encounters an assertion failure and terminates. This affects recursive resolvers with ECS enabled processing malicious or crafted responses.
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= 9.10.5= 9.11.6CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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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Check BIND versionRun 'named -v' or 'named -V' to retrieve the installed BIND versionAffected if Version is exactly 9.10.5 or 9.11.6
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Verify BIND is configured as a recursive resolverInspect the BIND configuration file (typically /etc/named.conf or /etc/bind/named.conf) for the 'recursion yes;' directiveAffected if Recursion is enabled ('recursion yes;' is present)
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Confirm EDNS Client Subnet is enabledSearch the BIND configuration file for 'edns-client-subnet' or 'ecs' related options. Check for 'edns-client-subnet' within options{} block or view blocksAffected if ECS feature is explicitly enabled in the configuration (any 'edns-client-subnet' directive with a non-zero scope)
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Check if named process is runningRun 'systemctl status named' or 'ps aux | grep named' to verify the DNS service is activeAffected if The named process is running and serving as a recursive resolver with ECS enabled
A system is affected only if it runs BIND version 9.10.5 or 9.11.6, is configured as a recursive resolver, and has the EDNS Client Subnet feature explicitly enabled in the configuration.
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 a BIND version beyond 9.11.6-S1, or disable the EDNS Client Subnet feature in the BIND configuration if upgrading is not immediately feasible. Monitor DNS service availability closely during remediation.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2019-6469 — 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-2019-6469 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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