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CVE-2021-3671· NVD / CVE Program· CNA redhat

A null pointer de-reference was found in the way samba kerberos server handled missing sname in TGS-REQ (Ticket Granting Server - Request).

Noroxi assessment

Priority: Monitor (action score 27/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2.1% (FIRST EPSS); higher than 81.7% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: heimdal (Alpine:v3.14) 7.7.1-r0; samba (Alpine:v3.14) 4.14.8-r0; samba (Alpine:v3.15) 4.15.0-r0.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to heimdal (Alpine:v3.14) 7.7.1-r0; samba (Alpine:v3.14) 4.14.8-r0; samba (Alpine:v3.15) 4.15.0-r0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Oct 12, 2021
Updated
Jun 17, 2026
EPSS
2.1% · 81th percentile

Report tools

JSON

Action score

27

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
sambasamba
debiandebian linux
netappmanagement services for element software
netappmanagement services for netapp hci
netappontap select deploy administration utility

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux10.0
  • debian debian linux11.0
  • netapp management services for element softwareall versions
  • netapp management services for netapp hciall versions
  • netapp ontap select deploy administration utilityall versions
  • samba samba4.14.0 and later · before 4.14.8
  • samba sambabefore 4.13.12

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a Samba

    • Fixed in samba 4.13.12, samba 4.14.8affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.14heimdalbefore 7.7.1-r07.7.1-r0
Alpine:v3.14sambafrom 4.14.0 · before 4.14.8-r04.14.8-r0
Alpine:v3.15sambafrom 4.14.0 · before 4.15.0-r04.15.0-r0
Debian:10heimdalbefore 7.5.0+dfsg-3+deb10u17.5.0+dfsg-3+deb10u1
Debian:11heimdalbefore 7.7.0+dfsg-2+deb11u27.7.0+dfsg-2+deb11u2
Debian:12heimdalbefore 7.7.0+dfsg-37.7.0+dfsg-3
Debian:12sambabefore 2:4.13.13+dfsg-12:4.13.13+dfsg-1
openSUSE:Leap 15.3libheimdalbefore 7.8.0-bp153.2.4.17.8.0-bp153.2.4.1
openSUSE:Leap 15.4libheimdalbefore 7.8.0-bp154.2.4.17.8.0-bp154.2.4.1
SUSE:Package Hub 15 SP3libheimdalbefore 7.8.0-bp153.2.4.17.8.0-bp153.2.4.1
SUSE:Package Hub 15 SP4libheimdalbefore 7.8.0-bp154.2.4.17.8.0-bp154.2.4.1

Same product

samba: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-7494Samba since version 3.5.0 and before 4.6.4, 4.5.10 and 4.4.14 is vulnerable to remote code execution vulnerability, allowing a malicious cliKEV
    99Now
  • CVE-2015-0240The Netlogon server implementation in smbd in Samba 3.5.x and 3.6.x before 3.6.25, 4.0.x before 4.0.25, 4.1.x before 4.1.17, and 4.2.x befor
    66This week
  • CVE-2003-0085Buffer overflow in the SMB/CIFS packet fragment re-assembly code for SMB daemon (smbd) in Samba before 2.2.8, and Samba-TNG before 0.3.1, al
    66This week

Published before and after this one in the same product

  • ← EarlierCVE-2021-20277May 12, 2021 · A flaw was found in Samba's libldb.
    31Monitor
  • ← EarlierCVE-2020-27840May 12, 2021 · A flaw was found in samba.
    31Monitor
  • Later →CVE-2021-43566Jan 11, 2022 · All versions of Samba prior to 4.13.16 are vulnerable to a malicious client using an SMB1 or NFS race to allow a directory to be created in
    10Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:heimdal7.7.1-r0 · Alpine:v3.14Package registry (OSV)
alpine:samba4.14.8-r0 · Alpine:v3.14Package registry (OSV)
debian:heimdal7.7.0+dfsg-3 · Debian:12Package registry (OSV)
debian:samba2:4.13.13+dfsg-1 · Debian:12Package registry (OSV)
opensuse:libheimdal7.8.0-bp154.2.4.1 · openSUSE:Leap 15.4Package registry (OSV)
suse:libheimdal7.8.0-bp154.2.4.1 · SUSE:Package Hub 15 SP4Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records