How severe is CVE-2021-43242?

CVE-2021-43242 has a CVSS 3.x base score of 7.6, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2021-43242 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43242?

CVE-2021-43242 primarily affects Microsoft Sharepoint Enterprise Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43242?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-43242 published?

CVE-2021-43242 was published on 2021-12-15 and last updated on 2026-06-17.

CVE-2021-43242

CVE-2021-43242 is a high-severity vulnerability in Microsoft Sharepoint Enterprise Server with a CVSS 3.x base score of 7.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.6)
CVSS v2: 3.5
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Sharepoint Enterprise Server
Published: 2021-12-15
Last modified: 2026-06-17

Description

Microsoft SharePoint Server Spoofing Vulnerability

Frequently asked questions

What is CVE-2021-43242?: Microsoft SharePoint Server Spoofing Vulnerability
How severe is CVE-2021-43242?: CVE-2021-43242 has a CVSS 3.x base score of 7.6, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2021-43242 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43242?: CVE-2021-43242 primarily affects Microsoft Sharepoint Enterprise Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43242?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-43242 published?: CVE-2021-43242 was published on 2021-12-15 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43242

Affected products (4)

cpe:2.3:a:microsoft:sharepoint_enterprise_server:2016:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:sharepoint_foundation:2013:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:sharepoint_server:-:*:*:*:subscription:*:*:*
cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*

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