CVE-2021-42305 json
Microsoft Exchange Server Spoofing Vulnerability
published 2021-11-10 4 y ago modified 2026-08-19 2 mo ago also EUVD-2021-29280
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 7.9%
- EPSS 7.9% chance of exploitation in 30 days, percentile 94%
- public exploits
- 0
- none known
Summary
Microsoft Exchange Server Spoofing Vulnerability
Patch / fix
- Microsoft Microsoft Exchange Server 2013 Cumulative Update 23 15.00.1497.026
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 21 15.01.2308.020
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 22 15.01.2375.017
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 10 15.02.0792.019
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 11 15.02.0986.014
Exploit prediction
7.87% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C |
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Affected products
- Microsoft Microsoft Exchange Server 2013 Cumulative Update 23
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 21
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 22
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 10
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 11
Classification
- Technology feeds
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2021-42305
vendor-advisory, patch
-
portal.msrc.microsoft.com
/en-US/security-guidance/advisory/CVE-2021-42305
patch, vendor-advisory
Sources
- CVE List CVE-2021-42305
- NVD CVE-2021-42305
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.