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CVE-2026-42897

Microsoft Exchange Server Spoofing Vulnerability

Published: May 14, 2026Updated: Jun 15, 2026 Sources: CVE List NVD BDUCWE-79
8.1HIGH
NVD MITRE
EPSS Score
5.6%
Top 8.0%
CISA KEV
Active Exploitation
Since May 15, 2026
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-79

Affected Products

Microsoft Corp
commercial·USaka Microsoft, microsoft corporation
Microsoft Exchange Server 2016 Cumulative Update 23On-prem
Operating Systems / itsm-monitoring
Microsoft Exchange Server 2019 Cumulative Update 14On-prem
Operating Systems / windows
Microsoft Exchange Server 2019 Cumulative Update 15On-premWeb App
Enterprise Software / itsm-monitoring
Microsoft Exchange Server Subscription Edition RTMOn-premWeb App
Enterprise Software / itsm-monitoring
exchange serverOn-prem
Operating Systems / windows
exchange server subscription editionOn-premWeb App
Enterprise Software / itsm-monitoring
and 4 more affected products View all →

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:May 15, 2026
Remediation due:May 29, 2026

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Official Patch Available
Workaround Available
Is your org exposed to CVE-2026-42897?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897
msrc.microsoft.com
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897
msrc.microsoft.com
https://undercodetesting.com/zero-day-alert-cve-2026-42897-turns-exchange-servers-into-silent-cyber-weapons-no-patch-in-sight-video/
undercodetesting.com
and 3 more references View all →
News mentions
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