PatchTheCVECVE-2018-5709: An issue was discovered in MIT Kerberos 5 (aka krb5) through 1.16
CVE-2018-5709 is a high-severity flaw (CVSS 7.5) affecting kerberos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
An issue was discovered in MIT Kerberos 5 (aka krb5) through 1.16. There is a variable "dbentry->n_key_data" in kadmin/dbutil/dump.c that can store 16-bit data but unknowingly the developer has assigned a "u4" variable to it, which is for 32-bit data. An attacker can use this vulnerability to affect other artifacts of the database as we know that a Kerberos database dump file contains trusted data.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 2.0% (top 19%) |
| CISA exploited list | No |
| Weakness | CWE-190 |
| Published | 2018-01-16 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2018-5709?
kerberos: upgrade to newer than 5-1.16. Exact commands for each OS are on this page.
Is CVE-2018-5709 being exploited?
CVE-2018-5709 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2018-5709 affect?
CVE-2018-5709 affects kerberos. Severity is high (CVSS 7.5). An issue was discovered in MIT Kerberos 5 (aka krb5) through 1.16. There is a variable "dbentry->n_key_data" in kadmin/dbutil/dump.c that can store 16-bit data but unknowingly the developer has assigned a "u4" variable to it, which is for 3
How urgent is CVE-2018-5709?
Priority 52/100. High severity; Remotely exploitable, no login, no user action
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