CVE-2021-33766Actively exploitedAdded to KEV 2022-01-18

Microsoft Exchange Server Information Disclosure

Microsoft, Exchange Server

Description

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

CVSS severity for this advisory hasn't been enriched from NVD yet, check back shortly.

EPSS, exploit probability

Critical

98.2%

estimated chance of real-world exploitation in the next 30 days, higher than 99.9% of every CVE FIRST.org scores

Refreshed 10/28/2026, via FIRST.org's EPSS model, not CVSS, this measures likelihood of exploitation, not how severe it would be.

Required action

Apply updates per vendor instructions.

CISA-recommended due date: 2022-02-01

CWE-287

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