Is CVE-2021-28478 in the CISA KEV catalog?

No. CVE-2021-28478 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-28478?

CVE-2021-28478 has a CVSS v3 base score of 7.6 (HIGH).

What is the EPSS score for CVE-2021-28478?

CVE-2021-28478 has an EPSS score of 1.57% (72th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-28478?

Install KB5001917 for Microsoft SharePoint Enterprise Server 2016. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2021-28478

HIGHEPSS 72th pctl

7.6

CVSS v3

NVD

Description

Microsoft SharePoint Server Spoofing Vulnerability

CWE-290

How to fix

Remediation Available

Microsoft SharePoint Enterprise Server 2016Microsoft

Install:KB5001917Microsoft

Microsoft SharePoint Foundation 2013 Service Pack 1Microsoft

Install:KB5001935Microsoft

Microsoft SharePoint Server 2019Microsoft

Install:KB5001916Microsoft

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeChanged

Impact

ConfidentialityHigh

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

1.57%probability of exploitation in 30 days

72ndpercentile

Elevated risk: more likely to be exploited than 72% of all known CVEs.

References

Patch1

portal.msrc.microsoft.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-02-28.