VulnerabilityAnalyzed
CVE-2021-33766
Microsoft Exchange Server Information Disclosure
KEVHIGH 7.3EPSS 98.1%
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 1 February 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Microsoft Exchange Server Information Disclosure Vulnerability
- CVSS 3.1
- 7.3 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- EPSS
- 98.14% probability · 100th percentile
- CISA KEV
- Listed 18 January 2022 · due 1 February 2022
- Affected
- microsoft/exchange server
- Source
- secure@microsoft.com
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-33766
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-33766Patch, Vendor Advisory
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33766Patch, Vendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-798/Third Party Advisory, VDB Entry
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.