CVE-2021-3671

Publication date 12 October 2021

Last updated 18 August 2025

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

Description

A null pointer de-reference was found in the way samba kerberos server handled missing sname in TGS-REQ (Ticket Granting Server - Request). An authenticated user could use this flaw to crash the samba server.

Read the notes from the security team

Status

Package Ubuntu Release Status
heimdal 25.10 questing
Not affected
25.04 plucky
Not affected
24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic
Not affected
22.04 LTS jammy
Not affected
21.10 impish Ignored end of life
21.04 hirsute Ignored end of life
20.04 LTS focal
Fixed 7.7.0+dfsg-1ubuntu1.1
18.04 LTS bionic
Fixed 7.5.0+dfsg-1ubuntu0.1
16.04 LTS xenial
Fixed 1.7~git20150920+dfsg-4ubuntu1.16.04.1+esm1
14.04 LTS trusty
Fixed 1.6~git20131207+dfsg-1ubuntu1.2+esm1
samba 25.10 questing
Fixed 2:4.13.14+dfsg-0ubuntu1
25.04 plucky
Fixed 2:4.13.14+dfsg-0ubuntu1
24.10 oracular
Fixed 2:4.13.14+dfsg-0ubuntu1
24.04 LTS noble
Fixed 2:4.13.14+dfsg-0ubuntu1
23.10 mantic
Fixed 2:4.13.14+dfsg-0ubuntu1
23.04 lunar
Fixed 2:4.13.14+dfsg-0ubuntu1
22.10 kinetic
Fixed 2:4.13.14+dfsg-0ubuntu1
22.04 LTS jammy
Fixed 2:4.13.14+dfsg-0ubuntu1
21.10 impish
Fixed 2:4.13.14+dfsg-0ubuntu0.21.10.1
21.04 hirsute
Fixed 2:4.13.14+dfsg-0ubuntu0.21.04.1
20.04 LTS focal
Fixed 2:4.13.14+dfsg-0ubuntu0.20.04.1
18.04 LTS bionic
Fixed 2:4.7.6+dfsg~ubuntu-0ubuntu2.26
16.04 LTS xenial
Vulnerable
14.04 LTS trusty
Vulnerable

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Notes

mdeslaur

same as CVE-2021-37750 for MIT krb5

Patch details

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

Package Patch details
heimdal
samba

Severity score breakdown

Parameter Value
Base score 6.5 · Medium
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-5142-1
    • Samba vulnerabilities
    • 11 November 2021
    • USN-5174-1
    • Samba vulnerabilities
    • 6 December 2021
    • USN-5675-1
    • Heimdal vulnerabilities
    • 13 October 2022

Other references