XSS in Microsoft Exchange_server
CVE-2026-42897
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.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.103 (93.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.
Affected products
- Microsoft Exchange_server — versions 2016, 2019
- Microsoft Exchange Server 2016 Cumulative Update 23 — versions 15.01.0.0
- Microsoft Exchange Server 2019 Cumulative Update 14 — versions 15.02.0.0
- Microsoft Exchange Server 2019 Cumulative Update 15 — versions 15.02.0.0
- Microsoft Exchange Server Subscription Edition Rtm — versions 15.02.0.0
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
- Microsoft Exchange Server Spoofing Vulnerability (vendor-advisory, patch, Mitigation, Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-42897?
- CVE-2026-42897 is a high-severity vulnerability in Microsoft Exchange_server, classified under Cross-site Scripting. CVSS score: 8.1/10. Published 2026-05-14.
- How severe is CVE-2026-42897?
- High severity. CVSS v3 base score is 8.1 out of 10.
- Is CVE-2026-42897 known to be exploited?
- Yes. CVE-2026-42897 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-15), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.