CVE-2021-1730 json
Microsoft Exchange Server Spoofing Vulnerability
published 2021-02-25 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-7194
- cvss
- 5.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.8%
- EPSS 1.8% chance of exploitation in 30 days, percentile 78%
- public exploits
- 0
- none known
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>
Patch / fix
Exploit prediction
1.82% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:O/RC:C |
| CNA | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N |
| NVD | 2.0 | 5.8 | AV:N/AC:M/Au:N/C:P/I:P/A:N |
Affected products
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 7
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 18
Classification
- Technology feeds
References
-
portal.msrc.microsoft.com
/en-US/security-guidance/advisory/CVE-2021-1730
patch, vendor-advisory
Sources
- CVE List CVE-2021-1730
- NVD CVE-2021-1730
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