Is CVE-2021-42309 in the CISA KEV catalog?

No. CVE-2021-42309 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-42309?

CVE-2021-42309 has a CVSS v3 base score of 8.8 (HIGH).

What is the EPSS score for CVE-2021-42309?

CVE-2021-42309 has an EPSS score of 2.66% (84th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-42309?

Install KB5002055 for Microsoft SharePoint Enterprise Server 2016. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2021-42309

HIGHEPSS 84th pctl

8.8

CVSS v3

NVD

Description

Microsoft SharePoint Server Remote Code Execution Vulnerability

CWE-94Code Injection CWE-732Incorrect Permission Assignment for Critical Resource

How to fix

Remediation Available

Microsoft SharePoint Enterprise Server 2016Microsoft

Install:KB5002055Microsoft

Microsoft SharePoint Foundation 2013 Service Pack 1Microsoft

Install:KB5002071Microsoft

Microsoft SharePoint Server 2019Microsoft

Install:KB5002054Microsoft

Microsoft SharePoint Server Subscription EditionMicrosoft

Install:KB5002045Microsoft

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 InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

2.66%probability of exploitation in 30 days

84thpercentile

Elevated risk: more likely to be exploited than 84% of all known CVEs.

References

Patch1

portal.msrc.microsoft.com

Third-Party Advisory1

zerodayinitiative.com

Related Vulnerabilities

Other CWE-94 (Code Injection) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2017-9841	Critical	9.8	100%	KEV	Fix
CVE-2015-1635	Critical	9.8	100%	KEV	-
CVE-2022-22954	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-22204	Medium	6.8	100%	KEV	Fix
CVE-2025-3248	Critical	9.8	100%	KEV	Fix
CVE-2012-0158	High	8.8	100%	KEV	-

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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 2024-11-21.