MIT Kerberos: security vulnerability (CVE-2003-0138)
Published Sources: CVE.org
What is affected, what to do
Version 4 of the Kerberos protocol (krb4), as used in Heimdal and other packages, allows an attacker to impersonate any principal in a realm via a chosen-plaintext attack.
The available sources name no fixed version. Check the vendor guidance in the references below.
- Affected
- MIT Kerberos
eq 4..4
- MIT Kerberos
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Metrics
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Priority
No value is available for this vulnerability.
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CVSS v3
No value is available for this vulnerability.
4.3 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 91.1
Show all metrics
- Severity
- Not rated
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 66.41 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 4.3 %
- Moderate — model estimates 1-10% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 91.1
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Version 4 of the Kerberos protocol (krb4), as used in Heimdal and other packages, allows an attacker to impersonate any principal in a realm via a chosen-plaintext attack.
Source: cvelistv5, NVD (NIST)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| mit | kerberos |
|
|
Vendors and products
References & sources
- debian.orgDSA-269Vendor advisory, x_refsource_DEBIAN
- redhat.comRHSA-2003:052Vendor advisory, x_refsource_REDHAT
- securityfocus.com20030331 GLSA: krb5 & mit-krb5 (200303-28)Mailing list, x_refsource_BUGTRAQ
- web.mit.edukerberos/www/advisories/MITKRB5-SA-2003-004-krb4.txtx_refsource_CONFIRM
- oval.cisecurity.orgoval:org.mitre.oval:def:248Vulnerability database, signature, x_refsource_OVAL
- redhat.comRHSA-2003:091Vendor advisory, x_refsource_REDHAT
- debian.orgDSA-273Vendor advisory, x_refsource_DEBIAN
- redhat.comRHSA-2003:051Vendor advisory, x_refsource_REDHAT
- kb.cert.orgVU#623217Third-party advisory, x_refsource_CERT-VN
- debian.orgDSA-266Vendor advisory, x_refsource_DEBIAN
- marc.info20030317 MITKRB5-SA-2003-004: Cryptographic weaknesses in Kerberos v4 protocolMailing list, x_refsource_BUGTRAQ
- securityfocus.com7113Vulnerability database, x_refsource_BID
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<a href="https://intel.neosec.eu/en/cve/CVE-2003-0138"><img src="https://intel.neosec.eu/badge/cve/CVE-2003-0138.svg?lang=en" alt="CVE-2003-0138 – NEOSEC Intel" height="20"></a>