---
cve: "CVE-2026-42897"
severity: "HIGH"
cvss: 8.1
epss: "70.7%"
vendor: "Microsoft"
kev: true
exploited: true
published: "2026-05-14 18:16:49"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-11-03T18:26:14+01:00"
---

# CVE-2026-42897

> 8.1 HIGH · ⚠️ CISA KEV (172 Tage) · 🔓 Exploited

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **microsoft**
- State: PUBLISHED
- Stand: 2026-08-10 15:14:02
- CNA-CVSS: **8.1** (`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`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA KEV seit: **15.05.2026**
- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **active**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Erforderlich | good |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Schwachstellen-Klasse

- **CWE-79** — Improper Neutralization of Input During Web Page Generation
  The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

## Angriffsmuster (CAPEC)

- [CAPEC-63 — Cross-Site Scripting (XSS)](https://capec.mitre.org/data/definitions/63.html) _(Severity: Very High)_
- [CAPEC-85 — AJAX Footprinting](https://capec.mitre.org/data/definitions/85.html) _(Severity: Low)_
- [CAPEC-209 — XSS Using MIME Type Mismatch](https://capec.mitre.org/data/definitions/209.html) _(Severity: Medium)_
- [CAPEC-588 — DOM-Based XSS](https://capec.mitre.org/data/definitions/588.html) _(Severity: Very High)_
- [CAPEC-591 — Reflected XSS](https://capec.mitre.org/data/definitions/591.html) _(Severity: Very High)_
- [CAPEC-592 — Stored XSS](https://capec.mitre.org/data/definitions/592.html) _(Severity: Very High)_

## BSI-Hinweise (deutsch)

- [Microsoft Exchange Server: Schwachstelle ermöglicht Cross-Site-Scripting- und Spoofing-Angriffe](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-1536) — _BSI-Einstufung: hoch_
  Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Microsoft Exchange Server ausnutzen, um Cross-Site-Scripting- und Spoofing-Angriffe durchzuführen.

## Referenzen

- <https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897>
- <https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42897>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-42897/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_