MEDIUM
CVE-2018-20217
CWE-617Published: December 26, 2018· Updated: Jun 17, 2026
5.3
CVSS v3.1
Official Description
A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket using an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.
Technical Analysis
CVE-2018-20217 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.3.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Vendors & Products
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (12)
→
http://krbdev.mit.edu/rt/Ticket/Display.html?id=8763Patch · Third Party Advisory
→
https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2019/01/msg00020.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/09/msg00019.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20190416-0006/Third Party Advisory
→
http://krbdev.mit.edu/rt/Ticket/Display.html?id=8763Patch · Third Party Advisory
→
https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2019/01/msg00020.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/09/msg00019.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20190416-0006/Third Party Advisory
Quick Facts
CVE IDCVE-2018-20217
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-617
CISA KEVNo
Affected2 vendor(s)
PublishedDec 26, 2018
Related CVEs (CWE-617)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2018-20217 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.