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CVE-2018-20217
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…
- 5.3MediumCVSS base score
- 1.4%Exploitation in 30 daysEPSS · top 27% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mitre
- 7 days later
· 7 days later
Published
- 6 years later
· 6 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.4% · top 27% of all CVEs (10 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Affected products
n/a
- affected n/a
References
6
- FEDORA-2018-7db7ccda4d (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- http://krbdev.mit.edu/rt/Ticket/Display.html?id=8763 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086 (opens in a new tab)x_refsource_CONFIRMx_transferred
- [debian-lts-announce] 20190125 [SECURITY] [DLA 1643-1] krb5 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- https://security.netapp.com/advisory/ntap-20190416-0006/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- [debian-lts-announce] 20210930 [SECURITY] [DLA 2771-1] krb5 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2018-12784 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2018-20217)Record last updated .