How severe is CVE-2021-40483?

CVE-2021-40483 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-2021-40483 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40483?

CVE-2021-40483 affects Microsoft Sharepoint Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40483?

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-2021-40483 published?

CVE-2021-40483 was published on 2021-10-13 and last updated on 2026-06-17.

CVE-2021-40483

CVE-2021-40483 is a high-severity vulnerability in Microsoft Sharepoint 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% (67th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Sharepoint Server
Published: 2021-10-13
Last modified: 2026-06-17

Description

Microsoft SharePoint Server Spoofing Vulnerability

Frequently asked questions

What is CVE-2021-40483?: Microsoft SharePoint Server Spoofing Vulnerability
How severe is CVE-2021-40483?: CVE-2021-40483 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-2021-40483 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40483?: CVE-2021-40483 affects Microsoft Sharepoint Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40483?: 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-2021-40483 published?: CVE-2021-40483 was published on 2021-10-13 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40483

Affected products (1)

cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*

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