Microsoft Exchange Server Remote Code Execution Vulnerability

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. Mar 2, 2021 · Catalog

   Detected

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

2. Nov 3, 2021 · CISA KEV

   Known exploited

   Apply updates per vendor instructions.

3. May 3, 2022 · CISA KEV

   Remediation due

   Apply updates per vendor instructions.

4. Oct 1, 2026 · Catalog

   Updated

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

Affected

• cpe microsoft/exchange server2013
• cpe microsoft/exchange server2016
• vendor Microsoft Exchange Serverversion unspecified

Sources

• CISA KEVConfirmed exploitationCVE-2021-26858

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

  cisa.gov
• CVE.orgVulnerability recordCVE-2021-26858

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2021-26858

  30-day exploitation probability 93.7%

  first.org
• NIST NVDVulnerability recordCVE-2021-26858

  Microsoft Exchange Server Remote Code Execution Vulnerability

  nvd.nist.gov

References

• Patch · msrc.microsoft.com
• CISA note · nvd.nist.gov
• Patch · portal.msrc.microsoft.com
• US Government Resource · cisa.gov
• CISA note · cisa.gov