Is CVE-2026-20963 in the CISA KEV catalog?

Yes. CVE-2026-20963 is on the CISA Known Exploited Vulnerabilities list, added 2026-03-18.

What is the CVSS severity of CVE-2026-20963?

CVE-2026-20963 has a CVSS v3 base score of 9.8 (Important).

What is the EPSS score for CVE-2026-20963?

CVE-2026-20963 has an EPSS score of 29.43% (98th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-20963?

Install KB5002828 for Microsoft SharePoint Enterprise Server 2016. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2026-20963

HIGHCISA KEVEPSS 98th pctl

9.8

CVSS v3

NVD

Description

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

CWE-502Deserialization of Untrusted Data

How to fix

Remediation Available

Microsoft SharePoint Enterprise Server 2016Microsoft

Install:KB5002828Microsoft

Microsoft SharePoint Server 2019Microsoft

Install:KB5002825Microsoft

Microsoft SharePoint Server Subscription EditionMicrosoft

Install:KB5002822Microsoft

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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 RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Exploit Intelligence

29.43%probability of exploitation in 30 days

98thpercentile

Very high risk: more likely to be exploited than 98% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Remediation due: 2026-03-21

References

Vendor Advisory1

msrc.microsoft.com

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-0669	High	7.2	100%	KEV + Ransom	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2021-35464	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-29300	Critical	9.8	100%	KEV + Ransom	-
CVE-2025-53770	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2022-41082	High	8.0	100%	KEV + Ransom	Fix

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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 2026-04-01.