Microsoft Exchange Server Information Disclosure

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. Jul 14, 2021 · Catalog

   Detected

   Microsoft Exchange Server contains an information disclosure vulnerability which can allow an unauthenticated attacker to steal email traffic from target.

2. Jan 18, 2022 · CISA KEV

   Known exploited

   Apply updates per vendor instructions.

3. Feb 1, 2022 · CISA KEV

   Remediation due

   Apply updates per vendor instructions.

4. Aug 10, 2026 · Catalog

   Updated

   Microsoft Exchange Server contains an information disclosure vulnerability which can allow an unauthenticated attacker to steal email traffic from target.

Affected

• cpe microsoft/exchange server2013
• cpe microsoft/exchange server2016
• cpe microsoft/exchange server2019
• vendor Microsoft Exchange Serverversion unspecified

Sources

• CISA KEVConfirmed exploitationCVE-2021-33766

  Microsoft Exchange Server contains an information disclosure vulnerability which can allow an unauthenticated attacker to steal email traffic from target.

  cisa.gov
• CVE.orgVulnerability recordCVE-2021-33766

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2021-33766

  30-day exploitation probability 98.2%

  first.org
• NIST NVDVulnerability recordCVE-2021-33766

  Microsoft Exchange Server Information Disclosure Vulnerability

  nvd.nist.gov

References

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