MEDIUM
CVE-2021-3671
CWE-476Published: October 12, 2021· Updated: Jun 17, 2026
6.5
CVSS v3.1
Official 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.
Technical Analysis
CVE-2021-3671 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.5.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Vendors & Products
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (14)
→
https://github.com/heimdal/heimdal/commit/04171147948d0a3636bc6374181926f0fb2ec83aPatch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2022/11/msg00034.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20221215-0002/Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20230216-0008/Third Party Advisory
→
https://www.debian.org/security/2022/dsa-5287Third Party Advisory
→
https://github.com/heimdal/heimdal/commit/04171147948d0a3636bc6374181926f0fb2ec83aPatch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2022/11/msg00034.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20221215-0002/Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20230216-0008/Third Party Advisory
→
https://www.debian.org/security/2022/dsa-5287Third Party Advisory
Quick Facts
CVE IDCVE-2021-3671
CVSS Score6.5 / 10
SeverityMEDIUM
WeaknessCWE-476
CISA KEVNo
Affected3 vendor(s)
PublishedOct 12, 2021
Related CVEs (CWE-476)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-3671 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.