Is CVE-2021-34453 in the CISA KEV catalog?

No. CVE-2021-34453 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34453?

CVE-2021-34453 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-34453?

CVE-2021-34453 has an EPSS score of 2.67% (84th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34453?

Install KB5007012 for Microsoft Exchange Server 2016 Cumulative Update 21. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2021-34453

HIGHEPSS 84th pctl

7.5

CVSS v3

NVD

Description

Microsoft Exchange Server Denial of Service Vulnerability

How to fix

Remediation Available

Microsoft Exchange Server 2016 Cumulative Update 21Microsoft

Install:KB5007012Microsoft

Microsoft Exchange Server 2016 Cumulative Update 22Microsoft

Install:KB5007012Microsoft

Microsoft Exchange Server 2019 Cumulative Update 10Microsoft

Install:KB5007012Microsoft

Microsoft Exchange Server 2019 Cumulative Update 11Microsoft

Install:KB5007012Microsoft

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

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

2.67%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

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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.