CVE-2018-20217

Publication date 26 December 2018

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

5.3 · Medium

Score breakdown

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.

From the Ubuntu Security Team

It was discovered that Kerberos incorrectly handled certain S4U2Self requests. An attacker could possibly use this issue to cause a denial of service.

Status

Package Ubuntu Release Status
krb5 22.10 kinetic
Not affected
22.04 LTS jammy
Not affected
21.10 impish
Not affected
21.04 hirsute
Not affected
20.10 groovy
Not affected
20.04 LTS focal
Not affected
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
Fixed 1.16-2ubuntu0.3
16.04 LTS xenial
14.04 LTS trusty

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
krb5

Severity score breakdown

Parameter Value
Base score 5.3 · Medium
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H