CVE Hub
CVE-2026-93633
Zimbra Collaboration Suite Briefcase CSS Sanitization Bypass via Non-ASCII Stylesheet Characters
Fetching some sources has been requested. Reload in about a minute to see them.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Attack conditions and impact
Derived from the CNA (via NVD) CVSS 3.1 vector| Metric | Value | Meaning |
|---|---|---|
| Attack vector AV | N | Network |
| Attack complexity AC | L | Low (easy) |
| Privileges required PR | L | Regular user |
| User interaction UI | R | Required |
| Scope S | C | Changed (affects other components) |
| Confidentiality C | L | Low |
| Integrity I | L | Low |
| Availability A | N | None |
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Description
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.
CVSS assessments
| Provider | Version | Score | Vector |
|---|---|---|---|
| NVD / [email protected] (Secondary) | 3.1 | 5.4 MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| CNA / rapid7 | 3.1 | 5.4 MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
Affected products and packages
CNA (CVE.org)
| Vendor | Product | Versions |
|---|---|---|
| Zimbra | Zimbra Collaboration Suite | affected: 0 … <= 10.1.20 default: unaffected |
Linux distribution status
References (2)
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories NVD, CNA vendor-advisory
- https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ NVD, CNA related