How severe is CVE-2021-3956?

CVE-2021-3956 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-3956 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3956?

CVE-2021-3956 affects Lenovo Xclarity Controller. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3956?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-3956 published?

CVE-2021-3956 was published on 2022-05-18 and last updated on 2026-06-17.

CVE-2021-3956

CVE-2021-3956 is a medium-severity vulnerability in Lenovo Xclarity Controller with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Lenovo Xclarity Controller
Published: 2022-05-18
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-3956?: 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.
How severe is CVE-2021-3956?: CVE-2021-3956 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-3956 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3956?: CVE-2021-3956 affects Lenovo Xclarity Controller. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3956?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-3956 published?: CVE-2021-3956 was published on 2022-05-18 and last updated on 2026-06-17.

References

https://support.lenovo.com/us/en/product_security/LEN-72074

Affected products (1)

cpe:2.3:a:lenovo:xclarity_controller:*:*:*:*:*:*:*:*

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