---
cve: "CVE-2026-93633"
severity: "MEDIUM"
cvss: 5.4
epss: "0.2%"
vendor: "Zimbra"
kev: false
exploited: false
published: "2026-10-23 14:17:57"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-10-29T15:16:23+01:00"
---

# CVE-2026-93633

> 5.4 MEDIUM

## Beschreibung

A CSS sanitization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user with Briefcase access to publish a document that displays attacker-controlled content under the Zimbra origin. When processing a stylesheet containing non-ASCII characters, DefangFilter appends the final ASCII segment without sanitizing it. HTML stored as application/x-zimbra-doc can therefore retain CSS URL references that the normal sanitizer removes. An attacker can share a crafted document that loads external resources and displays a credential-collection form using Zimbra's own visual assets. Exploitation requires the victim to open the document in a browser that renders the content type inline; credential theft additionally requires form submission. ZCS 10.1.16 and 10.1.20 are affected.

## CNA-Record (Kanon, cvelistV5)

- CNA: **rapid7**
- State: PUBLISHED
- Stand: 2026-10-28 19:51:07
- CNA-CVSS: **5.4** (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **partial**

## CVSS-Vektor

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

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

## Schwachstellen-Klasse

- **CWE-79** — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
  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)_

## Referenzen

- <https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories>
- <https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-93633/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_