---
title: "CVE-2018-5709\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2018-5709?format=md
keywords: index, follow
---

# CVE-2018-5709

Publication date 16 January 2018

Last updated 1 August 2025

---

Ubuntu priority

**Negligible**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2018-5709?format=md#impact-score)

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## Description

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.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2018-5709?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| krb5 | 22.04 LTS jammy | Ignored see notes |
| 21.10 impish | Ignored end of life |
| 21.04 hirsute | Ignored end of life |
| 20.10 groovy | Ignored end of life |
| 20.04 LTS focal | Ignored end of standard support, was ignored [see notes] |
| 19.10 eoan | Ignored end of life |
| 19.04 disco | Ignored end of life |
| 18.10 cosmic | Ignored end of life |
| 18.04 LTS bionic | Ignored end of standard support |
| 17.10 artful | Ignored end of life |
| 16.04 LTS xenial | Ignored end of standard support, was needed |
| 14.04 LTS trusty | Ignored end of standard support |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Notes

---

### [ebarretto](https://launchpad.net/~ebarretto)

according to debian security tracker: non-issue, codepath is
only run on trusted input, potential integer overflow is
non-issue

---

### [ccdm94](https://launchpad.net/~ccdm94)

no patch available in 2022-05-11. Unlikely to have a security
impact. This is not considered a security issue according to
various sources.

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | High |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-5709)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-5709)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-5709)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-5709)

### Other references

* <https://github.com/poojamnit/Kerberos-V5-1.16-Vulnerabilities/tree/master/Integer%20Overflow>
* <https://www.cve.org/CVERecord?id=CVE-2018-5709>