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Kerberos 5Application · Mit

CVE-2007-3999

HIGH · 10.0 CVSS v2.0 Published 2007-09-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
Stack-based buffer overflow in the svcauth_gss_validate function in lib/rpc/svc_auth_gss.c in the RPCSEC_GSS RPC library (librpcsecgss) in MIT Kerberos 5 (krb5) 1.4 through 1.6.2, as used by the Kerberos administration daemon (kadmind) and some third-party applications that use krb5, allows remote attackers to cause a denial of service (daemon crash) and probably execute arbitrary code via a long string in an RPC message.

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 confidence

Stack-based buffer overflow in the svcauth_gss_validate function in lib/rpc/svc_auth_gss.c in the RPCSEC_GSS RPC library (librpcsecgss) allows remote attackers to send a long string in an RPC message to cause denial of service (daemon crash) and potentially execute arbitrary code via the Kerberos administration daemon (kadmind) or third-party applications using krb5.

MitigationUpgrade MIT Kerberos 5 to version 1.6.3 or later which contains the patched svcauth_gss_validate function in librpcsecgss, or apply vendor-provided security patches.

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
Kerberos 5Application
Affected:= 1.4= 1.4.1= 1.4.2= 1.4.3= 1.4.4= 1.5= 1.5.1= 1.5.2= 1.5.3= 1.6= 1.6.1= 1.6.2

CVSS 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
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed MIT Kerberos 5 version
    Run 'krb5-config --version' or check package manager (dpkg -l krb5, rpm -q krb5, etc.)
    Affected if Version is 1.4, 1.4.1, 1.4.2, 1.4.3, 1.4.4, 1.5, 1.5.1, 1.5.2, 1.5.3, 1.6, 1.6.1, or 1.6.2
  2. Locate librpcsecgss library
    Search for lib/rpc/svc_auth_gss.c compiled library: check /usr/lib or /usr/lib64 for librpcsecgss* files, or use 'find /usr -name '*rpcsecgss*' 2>/dev/null'
    Affected if Library file exists and Kerberos version is in the affected range
  3. Check if kadmind daemon is running
    Run 'ps aux | grep kadmind' or check service status (systemctl/status kadmind, service kadmin status)
    Affected if kadmind daemon is active and Kerberos version is in the affected range
  4. Verify RPCSEC_GSS / GSSAPI RPC services in use
    Check for services using GSS-API authentication: review running network services, check /etc/krb5.conf for kadmind or other GSS-API service definitions, inspect 'rpcinfo -p' for RPC services
    Affected if Any GSS-API based RPC service is running and Kerberos version is in the affected range

Environment is affected if MIT Kerberos 5 version is 1.4 through 1.6.2 AND either kadmind or any application using librpcsecgss library is enabled/running.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade MIT Kerberos 5 to version 1.6.3 or later which contains the patched svcauth_gss_validate function in librpcsecgss, or apply vendor-provided security patches.

Recommended fix High confidence

MIT Kerberos 5 version 1.6.3 or later (preferably latest stable 1.21.x)

  1. 1. Identify the current version of MIT Kerberos 5 installed by running 'krb5-config --version' or checking the package manager
  2. 2. If version is 1.4.x through 1.6.2, plan for upgrade to a fixed release
  3. 3. Before upgrading, backup the Kerberos configuration files (typically in /etc/krb5.conf and /var/kerberos/krb5kdc/)
  4. 4. Obtain the fixed Kerberos 5 release from your OS vendor or the MIT Kerberos distribution (https://web.mit.edu/kerberos/dist/index.html)
  5. 5. Install the updated packages using your system's package manager or compile from source
  6. 6. Restart the Kerberos daemons (kadmind, krb5kdc) to load the fixed libraries
  7. 7. Verify the upgrade was successful by checking the new version
Caveat Minor: Upgrading may require updating configuration if using deprecated options; test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Kerberos 5 Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA6.0 h
34.0 hours of engineering $5,940
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2007-3999 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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