CVE-2012-1192
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 · uneditedThe resolver in Unbound before 1.4.11 overwrites cached server names and TTL values in NS records during the processing of a response to an A record query, which allows remote attackers to trigger continued resolvability of revoked domain names via a "ghost domain names" attack.
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 confidenceUnbound DNS resolver before 1.4.11 has a cache poisoning flaw where the resolver incorrectly overwrites cached NS record nameserver names and TTL values when processing responses to A record queries. This causes stale NS records to persist beyond their intended TTL, allowing 'ghost domain names' - revoked or expired domains - to continue resolving.
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<= 1.4.10= 0.0= 0.1= 0.2= 0.3= 0.4= 0.5= 0.6= 0.7= 0.7.1= 0.7.2= 0.8CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:P/A:P
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.
-
Check if Unbound is installedRun `unbound -V` or `unbound -h` to display version information, or use your package manager (e.g., `rpm -q unbound`, `dpkg -l unbound`, `yum list installed unbound`)Affected if Unbound is not installed - not affected. If installed, proceed to next step.
-
Identify the installed versionExamine the version output from `unbound -V`. Look for a version number in the format 1.4.x or 0.xAffected if Version is 1.4.10 or lower, or any 0.x version (0.0 through 0.8) - potentially affected. Versions 1.4.11 and later are not affected.
-
Confirm Unbound is running as a DNS resolverCheck process status with `ps aux | grep unbound` or `systemctl status unbound`. Review the configuration file (typically /etc/unbound/unbound.conf) for recursive resolver settings such as `num-threads`, `access-control`, or `forward-zone` sectionsAffected if Unbound is running as a caching recursive resolver - the vulnerable condition applies. If Unbound is only running as an authoritative server (no caching), the flaw does not apply.
-
Verify DNS caching is enabledInspect the Unbound configuration for cache-related settings. Look for `cache-max-ttl`, `cache-min-ttl`, or `prefetch` directives. By default Unbound enables caching; confirm it has not been explicitly disabled with `serve-expired: no` and `num-cache-entries: 0`Affected if Caching is enabled (the default) - the cache poisoning condition can occur. If caching is completely disabled, the flaw has no impact.
You are affected if Unbound is installed with a version of 1.4.10 or lower (or any 0.x version) AND is running as a caching recursive resolver with DNS caching enabled.
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 Unbound to version 1.4.11 or later to patch the cache handling logic. Verify that DNS resolution works correctly after the upgrade.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 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-2012-1192 — 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-2012-1192 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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
- No spam, self-promotion, credentials, or personal data