ReviewHigh

CVE-2021-33768

Microsoft Microsoft Exchange Server 2016 Cumulative Update 20, Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2019 Cumulative Update 10

CVE-2021-33768 affects Microsoft Microsoft Exchange Server 2016 Cumulative Update 20, Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2019 Cumulative Update 10. Review the CVSS score, exploitation signals, affected versions, remediation status, and linked source material before making a change.

CVSS: 8
EPSS: 1.29%
CISA KEV: Not listed
Published: 2021.07.15

PRIORITY ASSESSMENT

Review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability1.29%

Technical severityCVSS 8

Vulnerability overview

Affected product and versions

Product: Microsoft Microsoft Exchange Server 2016 Cumulative Update 20, Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2019 Cumulative Update 10
Affected versions: >= 15.01.0 < 15.01.2242.012, >= 15.01.0 < 15.01.2308.014, >= 15.02.0 < 15.02.0922.013, >= 15.02.0 < 15.02.0858.015, 2016, 2019
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Microsoft Microsoft Exchange Server 2016 Cumulative Update 20, Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2019 Cumulative Update 10 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE: Not available