CVE-2021-26855

critical Microsoft ⚠️ CISA KEV — Exploited in the Wild
CVSS v3 Base Score
9.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score
100.0%
Exploitation probability in 30 days
Top 0% most likely to be exploited
Attack Characteristics
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
High
Availability
None
Published: March 3, 2021 (2013 days ago)
Last Modified: August 19, 2026
Vendor: Microsoft
Source: NVD

⚠️ CISA Known Exploited Vulnerability

Added to KEV: 2021-11-03
Remediation Due: 2022-05-03 (⚠ 1587d overdue)
Ransomware Campaign: Known

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

CWE

CWE-918

Affected Products

microsoft exchange server

References

🔗 msrc.microsoft.com 🔗 packetstormsecurity.com 🔗 packetstormsecurity.com 🔗 packetstormsecurity.com 🔗 packetstormsecurity.com