Firetruck

CVE-2021-26858

KEV · Ransomware
Updated Oct 1, 2026 · PUBLISHED
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Description

Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.

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Affected packages

PackageVendor / ProductVersion rangeStatus
Microsoft Exchange Server 2013 Cumulative Update 21Microsoft / Microsoft Exchange Server 2013 Cumulative Update 21>= 15.00.0, < 15.00.1395.012affected
Microsoft Exchange Server 2013 Cumulative Update 22Microsoft / Microsoft Exchange Server 2013 Cumulative Update 22>= 15.00.0, < 15.00.1473.006affected
Microsoft Exchange Server 2013 Cumulative Update 23Microsoft / Microsoft Exchange Server 2013 Cumulative Update 23>= 15.00.0, < 15.00.1497.012affected
Microsoft Exchange Server 2016 Cumulative Update 10Microsoft / Microsoft Exchange Server 2016 Cumulative Update 10>= 15.01.0, < 15.01.1531.012affected
Microsoft Exchange Server 2016 Cumulative Update 11Microsoft / Microsoft Exchange Server 2016 Cumulative Update 11>= 15.01.0, < 15.01.1591.018affected
Microsoft Exchange Server 2016 Cumulative Update 12Microsoft / Microsoft Exchange Server 2016 Cumulative Update 12>= 15.01.0, < 15.01.1713.010affected
Microsoft Exchange Server 2016 Cumulative Update 13Microsoft / Microsoft Exchange Server 2016 Cumulative Update 13>= 15.01.0, < 15.01.1779.008affected
Microsoft Exchange Server 2016 Cumulative Update 14Microsoft / Microsoft Exchange Server 2016 Cumulative Update 14>= 15.01.0, < 15.01.1847.012affected
Microsoft Exchange Server 2016 Cumulative Update 15Microsoft / Microsoft Exchange Server 2016 Cumulative Update 15>= 15.01.0, < 15.01.1913.012affected
Microsoft Exchange Server 2016 Cumulative Update 16Microsoft / Microsoft Exchange Server 2016 Cumulative Update 16>= 15.01.0, < 15.01.1979.008affected
Microsoft Exchange Server 2016 Cumulative Update 17Microsoft / Microsoft Exchange Server 2016 Cumulative Update 17>= 15.01.0, < 15.01.2044.013affected
Microsoft Exchange Server 2016 Cumulative Update 18Microsoft / Microsoft Exchange Server 2016 Cumulative Update 18>= 15.01.0, < 15.01.2106.013affected
Microsoft Exchange Server 2016 Cumulative Update 19Microsoft / Microsoft Exchange Server 2016 Cumulative Update 19>= 15.01.0, < 15.01.2176.009affected
Microsoft Exchange Server 2016 Cumulative Update 8Microsoft / Microsoft Exchange Server 2016 Cumulative Update 8>= 15.01.0, < 15.01.1415.010affected
Microsoft Exchange Server 2016 Cumulative Update 9Microsoft / Microsoft Exchange Server 2016 Cumulative Update 9>= 15.01.0, < 15.01.1466.016affected
Microsoft Exchange Server 2019Microsoft / Microsoft Exchange Server 2019>= 15.02.0, < 15.02.0221.018affected
Microsoft Exchange Server 2019 Cumulative Update 1Microsoft / Microsoft Exchange Server 2019 Cumulative Update 1>= 15.02.0, < 15.01.1979.006affected
Microsoft Exchange Server 2019 Cumulative Update 2Microsoft / Microsoft Exchange Server 2019 Cumulative Update 2>= 15.02.0, < 15.02.0397.011affected
Microsoft Exchange Server 2019 Cumulative Update 3Microsoft / Microsoft Exchange Server 2019 Cumulative Update 3>= 15.02.0, < 15.02.0464.015affected
Microsoft Exchange Server 2019 Cumulative Update 4Microsoft / Microsoft Exchange Server 2019 Cumulative Update 4>= 15.02.0, < 15.02.0659.012affected
Microsoft Exchange Server 2019 Cumulative Update 5Microsoft / Microsoft Exchange Server 2019 Cumulative Update 5>= 15.02.0, < 15.02.0595.008affected
Microsoft Exchange Server 2019 Cumulative Update 6Microsoft / Microsoft Exchange Server 2019 Cumulative Update 6>= 15.02.0, < 15.02.0529.013affected
Microsoft Exchange Server 2019 Cumulative Update 7Microsoft / Microsoft Exchange Server 2019 Cumulative Update 7>= 15.02.0, < 15.02.0721.013affected
Microsoft Exchange Server 2019 Cumulative Update 8Microsoft / Microsoft Exchange Server 2019 Cumulative Update 8>= 15.02.0, < 15.02.0792.010affected