CVE-2021-3671

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-10-12 · updated 2026-06-17
Weakness: CWE-476

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.

Affected products

Debian Linux: 10.0, 11.0
NetApp Management Services For Element Software: all versions
NetApp Management Services For Netapp Hci: all versions
NetApp ONTAP Select Deploy administration utility: all versions
Samba: before 4.13.12; from 4.14.0 before 4.14.8 — fixed in 4.13.12, 4.14.8

How to fix

Upgrade to a fixed version: Samba 4.13.12, 4.14.8. Check the vendor advisory for mitigations.

References

https://bugzilla.redhat.com/show_bug.cgi?id=2013080%2C
https://bugzilla.samba.org/show_bug.cgi?id=14770%2C
https://github.com/heimdal/heimdal/commit/04171147948d0a3636bc6374181926f0fb2ec83a
https://lists.debian.org/debian-lts-announce/2022/11/msg00034.html
https://security.netapp.com/advisory/ntap-20221215-0002/
https://security.netapp.com/advisory/ntap-20230216-0008/
https://www.debian.org/security/2022/dsa-5287
https://bugzilla.redhat.com/show_bug.cgi?id=2013080%2C
https://bugzilla.samba.org/show_bug.cgi?id=14770%2C
https://github.com/heimdal/heimdal/commit/04171147948d0a3636bc6374181926f0fb2ec83a
https://lists.debian.org/debian-lts-announce/2022/11/msg00034.html
https://security.netapp.com/advisory/ntap-20221215-0002/

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