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NVD / CVE Program· CNA lenovo

CVE-2021-3956: A read-only authentication bypass vulnerability was reported in the Third Quarter 2021 release of Lenovo XClarity Controller (XCC) firmware

Noroxi assessment

Priority: Monitor (action score 21/100)

  • 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: 0.78% (FIRST EPSS); higher than 56.3% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

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 read-only authentication bypass vulnerability was reported in the Third Quarter 2021 release of Lenovo XClarity Controller (XCC) firmware affecting XCC devices configured in LDAP Authentication Only Mode and using an LDAP server that supports “unauthenticated bind”, such as Microsoft Active Directory. An unauthenticated user can gain read-only access to XCC in such a configuration, thereby allowing the XCC device configuration to be viewed but not changed. XCC devices configured to use local authentication, LDAP Authentication + Authorization Mode, or LDAP servers that support only “authenticated bind” and/or “anonymous bind” are not affected.

MediumCVSS 5.3 · v3.1—No exploit No fix recorded
Published
May 18, 2022
Updated
Jun 17, 2026
EPSS
0.7% · 56th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CNA vs NVD score

NVD
5.3
CNA · lenovo
4.3
1.0 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

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

Follow CVE-2021-3956

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
lenovoxclarity controller
lenovothinkagile hx1320
lenovothinkagile hx1321
lenovothinkagile hx1520-r
lenovothinkagile hx1521-r
lenovothinkagile hx2320-e
lenovothinkagile hx2321
lenovothinkagile hx3320
lenovothinkagile hx3321
lenovothinkagile hx3375
lenovothinkagile hx3376
lenovothinkagile hx3520-g

and 34 more

Affected versions

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

  • lenovo xclarity controllerbefore 7.22_cdi382o
  • lenovo xclarity controllerbefore 2.32_psi342n
  • lenovo xclarity controllerbefore 3.41_tei382m
  • lenovo xclarity controllerbefore 4.83_tei3c0n
  • lenovo xclarity controllerbefore 1.51_tgbt24l

Versions reported by the vendor

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

  • Lenovo XClarity Controller (XCC)

    • various Third Quarter 2021 releasesaffected

Same product

lenovo: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-38512A privilege escalation vulnerability was discovered in XCC that could allow an authenticated XCC user with elevated privileges to perform co
    28Monitor
  • CVE-2024-38511A privilege escalation vulnerability was discovered in an upload processing functionality of XCC that could allow an authenticated XCC user
    28Monitor
  • CVE-2024-38510A privilege escalation vulnerability was discovered in the SSH captive command shell interface that could allow an authenticated XCC user wi
    28Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2019-6195Feb 14, 2020 · An authorization bypass exists in Lenovo XClarity Controller (XCC) versions prior to 3.08 CDI340V, 3.01 TEI392O, 1.71 PSI328N where a valid
    19Monitor
  • ← EarlierCVE-2021-3473Apr 13, 2021 · An internal product security audit of Lenovo XClarity Controller (XCC) discovered that the XCC configuration backup/restore password may be
    19Monitor
  • Later →CVE-2024-38508Jul 26, 2024 · A privilege escalation vulnerability was discovered in the web interface or SSH captive command shell interface of XCC that could allow an a
    28Monitor

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

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

No commit or PR link among the references.

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).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

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

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

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

All records