CVE-2021-33766

High (7.3) in Microsoft Exchange Server. In CISA KEV since 2022-01-18. EPSS 98% chance of exploitation in the next 30 days.

EPSS

98% chance of exploitation in the next 30 days; higher than 99% of CVEs (scores of 2026-10-31)

CISA KEV

listed 2022-01-18, due 2022-02-01

Published

2021-07-14

Modified

2026-08-10

Record from

the NVD, synced 2026-10-19

Affected

• microsoft:exchange_server

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-33766
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33766
• https://www.zerodayinitiative.com/advisories/ZDI-21-798/
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766

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