Microsoft Exchange Server Spoofing Vulnerability
Summary
| CVE | CVE-2026-42897 |
|---|---|
| State | PUBLISHED |
| Assigner | microsoft |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-14 18:16:49 UTC |
| Updated | 2026-05-15 19:35:52 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 6.1 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS: 0.081900000 probability, percentile 0.923430000 (date 2026-06-03)
CISA KEV: Listed on 2026-05-15; due 2026-05-29; ransomware use Unknown
Problem Types: CWE-79 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 6.1 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| 3.1 | [email protected] | Secondary | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
| 3.1 | CNA | CVSS | 8.1 | HIGH | 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 |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
RequiredScope
ChangedConfidentiality
LowIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CISA Known Exploited Vulnerability
| Vendor | Microsoft |
|---|---|
| Product | Microsoft |
| Name | Microsoft Exchange Server Cross-Site Scripting Vulnerability |
| Required Action | Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. |
| Notes | https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-42897 ; https://learn.microsoft.com/en-us/exchange/plan-and-deploy/post-installation-tasks/security-best-practices/exchange-emergency-mitigation-service ; https://nvd.nist.gov/vuln/detail/CVE-2026-42897 |
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Microsoft | Exchange Server | - | All | All | All |
| Application | Microsoft | Exchange Server | 2016 | - | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_1 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_10 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_11 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_12 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_13 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_14 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_15 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_16 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_17 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_18 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_19 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_2 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_20 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_21 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_22 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_23 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_3 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_4 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_5 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_6 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_7 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_8 | All | All |
| Application | Microsoft | Exchange Server | 2016 | cumulative_update_9 | All | All |
| Application | Microsoft | Exchange Server | 2019 | - | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_1 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_10 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_11 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_12 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_13 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_14 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_2 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_3 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_4 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_5 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_6 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_7 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_8 | All | All |
| Application | Microsoft | Exchange Server | 2019 | cumulative_update_9 | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Microsoft | Microsoft Exchange Server 2016 Cumulative Update 23 | affected - | x64-based Systems |
| CNA | Microsoft | Microsoft Exchange Server 2019 Cumulative Update 14 | affected - | x64-based Systems |
| CNA | Microsoft | Microsoft Exchange Server 2019 Cumulative Update 15 | affected - | x64-based Systems |
| CNA | Microsoft | Microsoft Exchange Server Subscription Edition RTM | affected - | x64-based Systems |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.cisa.gov/known-exploited-vulnerabilities-catalog | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | www.cisa.gov | US Government Resource |
| msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897 | [email protected] | msrc.microsoft.com | Mitigation, Vendor Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
| CISA Known Exploited Vulnerabilities catalog | CISA | www.cisa.gov | kev |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.