CVE-2018-5709
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 was discovered in MIT Kerberos 5 (aka krb5) through 1.16. There is a variable "dbentry->n_key_data" in kadmin/dbutil/dump.c that can store 16-bit data but unknowingly the developer has assigned a "u4" variable to it, which is for 32-bit data. An attacker can use this vulnerability to affect other artifacts of the database as we know that a Kerberos database dump file contains trusted data.
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 confidenceIn MIT Kerberos 5 (krb5) through 1.16, the n_key_data field in kadmin/dbutil/dump.c is a 16-bit field but incorrectly receives a 32-bit (u4) variable assignment. This type mismatch can cause integer truncation or overflow when processing Kerberos database dump files, potentially allowing an attacker to corrupt or manipulate database artifacts by supplying oversized values in a malicious dump file.
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<= 5-1.16CVSS 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:3.0/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 installed MIT Kerberos versionRun 'kinit --version' or 'krb5-config --version' to determine the krb5 library version installed on the systemAffected if The version is 1.16 or earlier (any version through 1.16 is affected)
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Locate kadmin dbutil componentCheck for the presence of kadmin database utilities: look for 'dump' or 'dbutil' in the kadmin directory, typically found in /usr/lib/krb5/kadmin/ or /usr/sbin/Affected if The kadmin/dbutil/dump utility exists and is present on the system
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Determine if dump files are processedReview system logs, cron jobs, or backup scripts for usage of 'kadmin dump' or 'kdb5_util dump' commands that load or process Kerberos database dump filesAffected if The system uses kadmin or kdb5_util to load or process dump files from any source
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Check for recent or scheduled dump operationsSearch for dump file artifacts in typical locations such as /var/lib/krb5kdc/ or backup directories, and examine any automation that processes these filesAffected if Dump files exist or are routinely processed by the kadmin utilities on this system
You are affected if running krb5 version 1.16 or earlier AND the kadmin/dbutil/dump component is used to process Kerberos database dump files, as the type mismatch in the dump.c code will trigger during dump file loading.
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 krb5 version 1.16.1 or later which contains the fix. In the interim, strictly control access to kadmin utilities and prohibit loading of untrusted dump files into production Kerberos databases.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-5709 — 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-2018-5709 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
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