CVE-2026-42897Microsoft Exchange Server Spoofing Vulnerability

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.

8.1 HIGHEPSS 70.66%⚡ Known Exploited (CISA KEV)NVD: Analyzed

Last updated: 2026-10-26 14:10 UTC

OverviewCVSS details

8.1HIGHCVSS 3.1

Score source: microsoft (CNA)
NVD status: Analyzed
Published: May 14, 2026
Assigner: microsoft

Affected

Microsoft Exchange Server 2016 Cumulative Update 23 (Microsoft)

Versions: 15.01.0.0 before 15.01.2507.069
Fixed in: 15.01.2507.069

+3 more products →

Exploitation

Public exploit: None listed
CISA KEV: Listed · May 15, 2026
KEV due date: May 29, 2026
Ransomware use: Unknown
SSVC: Exploitation active · Automatable no · Impact total

EPSS · FIRST, scored Nov 8

70.66%chance of exploitation in 30 days

Higher than 99.39% of CVEs

CVSS 3.1 · microsoft (CNA)

8.1High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: None

CVSS 3.1 · microsoft (CNA)

8.1High

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

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: None

CVSS 3.1 · NVD

6.1Medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Changed
Confidentiality impact: Low
Integrity impact: Low
Availability impact: None

NVD status: Analyzed

Overview Affected Products References

NVD CVE.org

Overview

Severity

Score	Severity	Version	Vector String
8.1	HIGH	3.1microsoft (CNA)	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
8.1	HIGH	3.1microsoft (CNA)	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
6.1	MEDIUM	3.1NVD	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CISA required action

⚡ Known exploited · remediation due May 29, 2026

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

Details

CVE ID: CVE-2026-42897
Status: Analyzed
Assigner (CNA): microsoft
Published: May 14, 2026
Last modified: 2026-10-26 14:10 UTC
Weaknesses: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Sources

Refreshed hourly from the sources above. Last fetched 2026-11-09 10:18 UTC.