How severe is CVE-2021-26420?

CVE-2021-26420 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2021-26420 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26420?

CVE-2021-26420 primarily affects Microsoft Sharepoint Enterprise Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26420?

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-2021-26420 published?

CVE-2021-26420 was published on 2021-06-08 and last updated on 2026-06-17.

CVE-2021-26420

CVE-2021-26420 is a high-severity vulnerability in Microsoft Sharepoint Enterprise Server with a CVSS 3.x base score of 7.1. 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 7.1)
CVSS v2: 6.5
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Sharepoint Enterprise Server
Published: 2021-06-08
Last modified: 2026-06-17

Description

Microsoft SharePoint Server Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2021-26420?: Microsoft SharePoint Server Remote Code Execution Vulnerability
How severe is CVE-2021-26420?: CVE-2021-26420 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2021-26420 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26420?: CVE-2021-26420 primarily affects Microsoft Sharepoint Enterprise Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26420?: 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-2021-26420 published?: CVE-2021-26420 was published on 2021-06-08 and last updated on 2026-06-17.

References

Affected products (3)

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:2019:*:*:*:*:*:*:*

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