CRITICAL CISA KEV Actively Exploited

CVE-2026-42897

Microsoft Exchange Server Spoofing Vulnerability

CVSS v3

8.1

CRITICAL

EPSS Score

2.5 %

exploit probability

CISA KEV

Yes

known exploited

Exploitation

active

SSVC status

Description

Microsoft Security Update (CVE-2026-42897)

CISA Known Exploited Vulnerability

Date Added: 2026-05-15
Patch Due Date: 2026-05-29
Ransomware Use: Unknown

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:F/RL:O/RC:C
Published: 2026-06-01
MSRC Title: Microsoft Exchange Server Spoofing Vulnerability
CERT-FR Advisory: CERTFR-2026-ALE-005
CERT-FR Link: CERTFR-2026-ALE-005

Frequently asked questions

What is CVE-2026-42897?

Microsoft Security Update (CVE-2026-42897)

Is CVE-2026-42897 actively exploited?

Yes. CVE-2026-42897 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-05-29.

What is the CVSS score for CVE-2026-42897?

CVE-2026-42897 has a CVSS v3 base score of 8.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:F/RL:O/RC:C.

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