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TI-2021-01446 Aliases CVE-2021-1730GHSA-mp5r-32pv-q987

Microsoft Exchange Server Spoofing Vulnerability

Priority LOW 28Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

<p>A spoofing vulnerability exists in Microsoft Exchange Server which could result in an attack that would allow a malicious actor to impersonate the user.</p> <p>This update addresses this vulnerability.</p> <p>To prevent these types of attacks, Microsoft recommends customers to download inline images from different DNSdomains than the rest of OWA. Please see further instructions in the FAQ to put in place this mitigations.</p>

Why it matters now

EPSS 0.01817 78th percentileScored 2026-11-07
Fix Fixed Microsoft Exchange Server 2019 Cumulative Update 7 (Microsoft): publicationMicrosoft Exchange Server 2016 Cumulative Update 18 (Microsoft): publication

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 715.02.0 to before publicationpublicationPatch availableCNA
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1815.01.0 to before publicationpublicationPatch availableCNA
  • Microsoft Exchange Server 2019 Cumulative Update 7 VendorMicrosoft Affected 15.02.0 to before publication Fixed in publication Patch available CNA
  • Microsoft Exchange Server 2016 Cumulative Update 18 VendorMicrosoft Affected 15.01.0 to before publication Fixed in publication Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_18:*:*:*:*:*:*2016 cumulative_update_18VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_7:*:*:*:*:*:*2019 cumulative_update_7VulnerableMicrosoft
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_18:*:*:*:*:*:* Versions 2016 cumulative_update_18 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_7:*:*:*:*:*:* Versions 2019 cumulative_update_7 Vulnerable ·Microsoft

Remediation

  • Fix · CNA Microsoft Exchange Server 2019 Cumulative Update 7 (Microsoft) Fixed in publication
  • Fix · CNA Microsoft Exchange Server 2016 Cumulative Update 18 (Microsoft) Fixed in publication

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-1730
  2. 2026-10-03 Alias added: GHSA-mp5r-32pv-q987

References

Patch 1

  • TI-2024-14170 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-19610 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-13547 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-13502 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-08465 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-07929 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1HIGH 8.8
See all 258 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences