CRITICAL CISA KEV Actively Exploited
CVE-2026-42897
Microsoft Exchange Server Spoofing Vulnerability
CVSS v3
8.1
CRITICAL
EPSS Score
0.5 %
exploit probability, as of 2026-10-20
CISA KEV
Yes
known exploited
Exploitation
active
SSVC status
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Affected and fixed versions
Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-42897 yet.
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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