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CVE-2021-33766

HIGH
Published 2021-07-14T17:53:40.000Z
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CVSS Score

V3.1
7.3
/10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C
Base Score Metrics
Exploitability: N/A Impact: N/A

EPSS Score

v2025.03.14
0.915
probability
of exploitation in the wild

There is a 91.5% chance that this vulnerability will be exploited in the wild within the next 30 days.

Updated: 2025-06-25
Exploit Probability
Percentile: 0.996
Higher than 99.6% of all CVEs

Attack Vector Metrics

Attack Vector
Not Available
Attack Complexity
Not Available
Privileges Required
Not Available
User Interaction
Not Available
Scope
Not Available

Impact Metrics

Confidentiality
Not Available
Integrity
Not Available
Availability
Not Available

Description

No description available

Microsoft Exchange Server Information Disclosure Vulnerability

Understanding This Vulnerability

This Common Vulnerabilities and Exposures (CVE) entry provides detailed information about a security vulnerability that has been publicly disclosed. CVEs are standardized identifiers assigned by MITRE Corporation to track and catalog security vulnerabilities across software and hardware products.

The severity rating (HIGH) indicates the potential impact of this vulnerability based on the CVSS (Common Vulnerability Scoring System) framework. Higher severity ratings typically indicate vulnerabilities that could lead to more significant security breaches if exploited. Security teams should prioritize remediation efforts based on severity, exploit availability, and the EPSS (Exploit Prediction Scoring System) score, which predicts the likelihood of exploitation in the wild.

If this vulnerability affects products or systems in your infrastructure, we recommend reviewing the affected products section, checking for available patches or updates from vendors, and implementing recommended workarounds or solutions until a permanent fix is available. Organizations should also monitor security advisories and threat intelligence feeds for updates about active exploitation of this vulnerability.

Available Exploits

Microsoft Exchange - Authentication Bypass

Microsoft Exchange Server Information Disclosure Vulnerability. This vulnerability enables an attacker to bypass authentication and gain access to the Exchange Server's internal.

ID: CVE-2021-33766
Author: daffainfo High

Related News

No news articles found for this CVE.

Affected Products

References

Known Exploited Vulnerability

This vulnerability is actively being exploited in the wild

View KEV Details

Remediation Status

Overdue

Due Date

February 1, 2022

Added to KEV

January 18, 2022

Required Action

Apply updates per vendor instructions.

Affected Product

Vendor/Project: Microsoft
Product: Exchange Server

Ransomware Risk

Known Ransomware Use
KEV Catalog Version: 2025.01.24 Released: January 24, 2025

GitHub Security Advisories

Community-driven vulnerability intelligence from GitHub

⚠ Unreviewed HIGH

GHSA-f9f4-96j3-5mvr

Advisory Details

Microsoft Exchange Information Disclosure Vulnerability

CVSS Scoring

CVSS Score

7.5

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Advisory provided by GitHub Security Advisory Database. Published: May 24, 2022, Modified: October 22, 2025

References

Published: 2021-07-14T17:53:40.000Z
Last Modified: 2025-07-28T19:48:02.879Z
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