Cyber Posture

CVE-2026-42897

HighCISA KEVActive Exploitation

Published: 14 May 2026

Published
14 May 2026
Modified
15 May 2026
KEV Added
15 May 2026
Patch
CVSS Score 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS Score 0.1234 94.0th percentile
Risk Priority 44 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-42897 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Microsoft Exchange Server. Its CVSS base score is 8.1 (High).

Operationally, ranked in the top 6.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

NVD 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.

Deeper analysisAI

Automated synthesis unavailable for this CVE.

Details

CWE(s)
KEV Date Added
15 May 2026

Affected Products

microsoft
exchange server
2016, 2019, all versions

CVEs Like This One

CVE-2025-66376Same product class: email / collaborationboth on KEV
CVE-2025-68461Same product class: email / collaborationboth on KEV
CVE-2025-27915Same product class: email / collaborationboth on KEV
CVE-2026-21510Same vendor: Microsoftboth on KEV
CVE-2025-59230Same vendor: Microsoftboth on KEV
CVE-2025-24985Same vendor: Microsoftboth on KEV
CVE-2026-21514Same vendor: Microsoftboth on KEV
CVE-2025-24993Same vendor: Microsoftboth on KEV
CVE-2025-24990Same vendor: Microsoftboth on KEV
CVE-2025-21391Same vendor: Microsoftboth on KEV

References