High [CVE-2021-26858] Microsoft Exchange Server Remote Code Execution Vulnerability
This high-severity Microsoft Server advisory covers CVE-2021-26858 affecting Microsoft Exchange Server 2013 Cumulative Update 22, Microsoft Exchange Server 2019 Cumulative Update 2, Microsoft Exchange Server 2016 Cumulative Update 13.
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Summary
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected products named by the advisory: Microsoft Exchange Server 2019; Microsoft Exchange Server 2013 Cumulative Update 22; Microsoft Exchange Server 2019 Cumulative Update 2; Microsoft Exchange Server 2016 Cumulative Update 13; and 20 more.
Affected products named by the advisory: Microsoft Exchange Server 2013 Cumulative Update 23; Microsoft Exchange Server 2019 Cumulative Update 3; Microsoft Exchange Server 2016 Cumulative Update 14; Microsoft Exchange Server 2019 Cumulative Update 4; and 16 more.
CISA Known Exploited Vulnerability
- Listed:
- Nov 3, 2021 · federal remediation due May 3, 2022
- 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 2019 15.02.0 before publication
- Microsoft Exchange Server 2013 Cumulative Update 22 15.00.0 before publication
- Microsoft Exchange Server 2019 Cumulative Update 2 15.02.0 before publication
- Microsoft Exchange Server 2016 Cumulative Update 13 15.01.0 before publication
- Microsoft Exchange Server 2013 Cumulative Update 23 15.00.0 before publication
- Microsoft Exchange Server 2019 Cumulative Update 3 15.02.0 before publication
- Microsoft Exchange Server 2016 Cumulative Update 14 15.01.0 before publication
- Microsoft Exchange Server 2019 Cumulative Update 4 15.02.0 before publication
- Microsoft Exchange Server 2016 Cumulative Update 15 15.01.0 before publication
- Microsoft Exchange Server 2019 Cumulative Update 5 15.02.0 before publication
- Microsoft Exchange Server 2019 Cumulative Update 6 15.02.0 before publication
- Microsoft Exchange Server 2016 Cumulative Update 16 15.01.0 before publication
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
- publication
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation
Upgrade to a fixed release: publication. 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 1 hour ago·verify at source
Discussion(0)
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