High [CVE-2021-42321] Microsoft Exchange Server Remote Code Execution Vulnerability
This high-severity Microsoft Server advisory covers CVE-2021-42321 affecting Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2016 Cumulative Update 22, Microsoft Exchange Server 2019 Cumulative Update 10.
Android app · Google Play
Monitor future Microsoft Server CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Summary
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected products named by the advisory: Microsoft Exchange Server 2016 Cumulative Update 21; Microsoft Exchange Server 2016 Cumulative Update 22; Microsoft Exchange Server 2019 Cumulative Update 10; Microsoft Exchange Server 2019 Cumulative Update 11.
CISA Known Exploited Vulnerability
- Listed:
- Nov 17, 2021 · federal remediation due Dec 1, 2021
- Required action:
- Apply updates per vendor instructions.
- Ransomware use:
- Known
KEV is a prioritization signal from CISA — remediation detail still comes from the vendor advisory.
- Microsoft Exchange Server 2016 Cumulative Update 21 15.01.0 before 15.01.2308.020
- Microsoft Exchange Server 2016 Cumulative Update 22 15.0.0 before 15.01.2375.017
- Microsoft Exchange Server 2019 Cumulative Update 10 15.02.0 before 15.02.0792.019
- Microsoft Exchange Server 2019 Cumulative Update 11 15.02.0 before 15.02.0986.014
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
- 15.01.2308.020
- 15.01.2375.017
- 15.02.0792.019
- 15.02.0986.014
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation
Upgrade to a fixed release: 15.01.2308.020, 15.01.2375.017, 15.02.0792.019, 15.02.0986.014. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.