CVE-2021-423218.8High

CVE-2021-42321: Microsoft Exchange Server Remote Code Execution Vulnerability

Microsoft · Microsoft Exchange Server 2016 Cumulative Update 21

Vendor fix available · Affected: Microsoft Exchange Server 2016 Cumulative Update 21 · Exploitation: in CISA KEV since 17 Nov 2021

Known ransomware use

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

ExploitationIn CISA KEV

In CISA KEVCISA KEV catalogue17 Nov 2021
Exploited (reported): not seen
Scanning observed: not seen
Proof of concept public: not seen
Not established: not seen

91.7%probability of exploitation in the next 30 days

99th percentile

050100

Higher than 99% of scored CVEs

8.8HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

Microsoft Exchange Server Remote Code Execution Vulnerability

Affected products4

From the CVE record. A product or version that is not listed is unknown, not unaffected.

Microsoft · Microsoft Exchange Server 2016 Cumulative Update 21from 15.01.0 before 15.01.2308.020
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 22from 15.0.0 before 15.01.2375.017
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 10from 15.02.0 before 15.02.0792.019
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 11from 15.02.0 before 15.02.0986.014

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalogue.
CISA KEV: Listed since 17 Nov 2021 · known ransomware use · catalogue entry
Public check: No public nuclei template
Vendor: Microsoft
Published: November 2021
Band: Exploited in the wild, November 2021

What changed

5 Nov
CISA’s KEV entry now notes known ransomware use CISA
17 Nov 2021
CISA added it to the KEV catalogue CISA

CoverageNo articles yet

No CyberSIXT article names CVE-2021-42321 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.