CVE-1999-1321
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 · uneditedBuffer overflow in ssh 1.2.26 client with Kerberos V enabled could allow remote attackers to cause a denial of service or execute arbitrary commands via a long DNS hostname that is not properly handled during TGT ticket passing.
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 confidenceBuffer overflow vulnerability in SSH 1.2.26 client with Kerberos V enabled allows remote attackers to cause denial of service or execute arbitrary code via a long DNS hostname that is not properly bounds-checked during TGT (Ticket Granting Ticket) ticket passing.
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= vCVSS 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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/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.
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Identify SSH client versionRun 'ssh -V' or 'ssh -v' to display the SSH client version. Alternatively, check the binary or package version using 'dpkg -l | grep ssh', 'rpm -qa | grep ssh', or by examining the SSH binary directly with 'file /usr/bin/ssh'Affected if The version is exactly SSH 1.2.26 or falls within the 1.2.x legacy branch prior to fixes
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Confirm Kerberos V support is compiled or enabledCheck the SSH client compilation flags or configuration: run 'ssh -V' for build options, examine the SSH binary with 'ldd /usr/bin/ssh' for kerberos libraries, or review the SSH source configuration for '--with-kerberos5' or '--with-kerberos4' flags if source is availableAffected if Kerberos V (KRB5) support is built into or enabled for the SSH client
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Inspect Kerberos ticket handling configurationReview /etc/krb5.conf and any SSH-specific Kerberos configuration files for TGT forwarding settings. Check if 'GSSAPIDelegateCredentials' or legacy Kerberos ticket forwarding options are enabled in ~/.ssh/config or /etc/ssh/ssh_configAffected if TGT ticket passing or credential delegation is configured and the client connects to remote hosts using Kerberos authentication
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Verify DNS resolution behavior during Kerberos authObserve SSH connection logs with verbose mode ('ssh -v') during Kerberos authentication. The vulnerability triggers when the SSH client resolves a hostname containing excessive label lengths during TGT passingAffected if Long DNS hostnames are used and Kerberos TGT tickets are processed through the vulnerable code path
You are affected if you are running SSH 1.2.26 with Kerberos V support enabled and using Kerberos authentication where TGT tickets are passed to remote hosts with DNS hostnames not properly bounds-checked.
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 modern version of SSH (such as current OpenSSH releases) that does not contain this vulnerability. If Kerberos V support is required, ensure the newer SSH version includes properly bounds-checked Kerberos integration.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-1999-1321 — 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-1999-1321 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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