CVE-2026-42897
mediumpriority · act · 90OT risk · criticalKEV · exploitedEU KEV · CERT.PLEPSS 0.005 · 43 %ileexploit · PoCDEEUNLRUUSadded 2026-05-15remediate by 2026-05-29
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.
EU KEVflagged by CERT.PLreported 2026-08-18patched 2026-05-14
EPSS · scored 2026-10-22
Microsoft Exchange Server Cross-Site Scripting 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.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedMicrosoft Exchange Server 2016 Cumulative Update 23msrc_csaf
15.01.2507.069:Security Update:https://support.microsoft.com/help/5094144
https://support.microsoft.com/help/5094144 - FixedMicrosoft Exchange Server 2019 Cumulative Update 14msrc_csaf
15.02.1544.041:Security Update:https://support.microsoft.com/help/5094142
https://support.microsoft.com/help/5094142 - FixedMicrosoft Exchange Server 2019 Cumulative Update 15msrc_csaf
15.02.1748.046:Security Update:https://support.microsoft.com/help/5094140
https://support.microsoft.com/help/5094140 - FixedMicrosoft Exchange Server Subscription Edition RTMmsrc_csaf
15.02.2562.043:Security Update:https://support.microsoft.com/help/5094139
https://support.microsoft.com/help/5094139
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.1–8.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
affected products (26)
Products and version ranges known to be affected.
- Microsoft Exchange Server 2016 Cumulative Update 23all versionscert_bundDEcpe:/a:microsoft:exchange:server_2016_cumulative_update_23
- Microsoft Exchange Server 2019 Cumulative Update 14all versionscert_bundDEcpe:/a:microsoft:exchange:server_2019_cumulative_update_14
- Microsoft Exchange Server Subscription Edition RTMall versionscert_bundDEcpe:/a:microsoft:exchange:server_subscription_edition_rtm
advisories (3)
Vendor and ecosystem advisories describing this.
- NCSC-2026-0159Kwetsbaarheid verholpen in Microsoft Exchange ServerNL2026-05-15csaf · ncsc_nlNL
Microsoft heeft een kwetsbaarheid verholpen in Microsoft Exchange Server.
- WID-SEC-W-2026-1536Microsoft Exchange Server: Schwachstelle ermöglicht Cross-Site-Scripting- und Spoofing-AngriffeDeutsch2026-05-14csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Microsoft Exchange Server ausnutzen, um Cross-Site-Scripting- und Spoofing-Angriffe durchzuführen.
- msrc_CVE-2026-42897Microsoft Exchange Server Spoofing Vulnerability2026-05-14csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (5)
External citations — patches, advisories, analysis.
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2026-42897cnnvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897enisa_euvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897MitigationVendor Advisorynvd
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42897US Government Resourcenvd
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