HOMEVULNERABILITIESCVE-2021-45100
HIGH

CVE-2021-45100

CWE-319Published: December 16, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

The ksmbd server through 3.4.2, as used in the Linux kernel through 5.15.8, sometimes communicates in cleartext even though encryption has been enabled. This occurs because it sets the SMB2_GLOBAL_CAP_ENCRYPTION flag when using the SMB 3.1.1 protocol, which is a violation of the SMB protocol specification. When Windows 10 detects this protocol violation, it disables encryption.

NVD Source

Technical Analysis

CVE-2021-45100 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected Vendors & Products

ksmbd_project1 product(s)
ksmbd
Linux1 product(s)
linux kernel
netapp16 product(s)
h410c firmwareh410ch300s firmwareh300sh500s firmwareh500sh700s firmwareh700sh300e firmwareh300eh500e firmwareh500e+4
Source: NVD CPE · 18 total CPE entries

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

PATCHhttps://github.com/cifsd-team/ksmbd/pull/551
PATCHhttps://github.com/cifsd-team/ksmbd/pull/551
ADVISORYhttps://github.com/cifsd-team/ksmbd/issues/550
ADVISORYhttps://marc.info/?l=linux-kernel&m=163961726017023&w=2
ADVISORYhttps://security.netapp.com/advisory/ntap-20220107-0001/
ADVISORYhttps://github.com/cifsd-team/ksmbd/issues/550
ADVISORYhttps://marc.info/?l=linux-kernel&m=163961726017023&w=2
ADVISORYhttps://security.netapp.com/advisory/ntap-20220107-0001/

All References (8)

→
https://github.com/cifsd-team/ksmbd/issues/550Third Party Advisory
→
https://github.com/cifsd-team/ksmbd/pull/551Patch · Third Party Advisory
→
https://marc.info/?l=linux-kernel&m=163961726017023&w=2Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20220107-0001/Third Party Advisory
→
https://github.com/cifsd-team/ksmbd/issues/550Third Party Advisory
→
https://github.com/cifsd-team/ksmbd/pull/551Patch · Third Party Advisory
→
https://marc.info/?l=linux-kernel&m=163961726017023&w=2Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20220107-0001/Third Party Advisory

Quick Facts

CVE IDCVE-2021-45100
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-319
CISA KEVNo
Affected3 vendor(s)
PublishedDec 16, 2021

Related CVEs (CWE-319)

CVE-2025-47419
10.0
CVE-2025-4378
10.0
CVE-2020-5594
9.8
CVE-2018-11422
9.8
CVE-2018-11421
9.8
CVE-2019-18852
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-45100 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.
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