CVE-2026-42897

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.

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

• 8.1CVSS 3.1, Highfrom the CNA (microsoft)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

What to do

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

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Timeline

1. 14 May 2026 Published
2. 15 May 2026 CVE-2026-42897 added to CISA KEV
3. 15 May 2026 Added to the CISA KEV catalogue

Weakness

• CWE-79

References

• Microsoft Exchange Server Spoofing Vulnerabilityvendor-advisorypatch