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CVE-2021-1730

Microsoft Exchange Server Spoofing Vulnerability

Published: Feb 25, 2021Updated: Feb 24, 2026 Sources: CVE List NVD BDUNVD-CWE-noinfo
5.4MEDIUM
NVD MITRE
EPSS Score
1.8%
Top 24.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

<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>

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:UC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
Open in CVSS calculator →

Weaknesses

NVD-CWE-noinfo

Affected Products

Microsoft Exchange Server 2019 Cumulative Update 7Microsoft
On-premOS
Operating Systems / windows
Microsoft Exchange Server 2016 Cumulative Update 18Microsoft
On-premOS
Operating Systems / windows
Microsoft Exchange ServerMicrosoft Corp
On-prem
Operating Systems
exchange servermicrosoft
On-prem
Operating Systems / windows
microsoftcommercialUSOperating Systems
microsoft corpcommercialUSOperating Systemsaka microsoft corporation

Exploitability

Official Patch Available

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1730
portal.msrc.microsoft.com
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-1730&#13;
msrc.microsoft.com
https://www.cybersecurity-help.cz/vdb/SB2021020931
cybersecurity-help.cz

Timeline

Published
Feb 25, 2021
Last Updated
Feb 24, 2026

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