CVE-2026-93633 Details
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.
View at NVD
Exploit prediction scoring system (EPSS) score for CVE-2026-93633
EPSS (Exploit Prediction Scoring System): EPSS predicts the likelihood that a vulnerability will be exploited in the wild. A higher percentage means a greater chance of an exploit occurring. The EPSS model produces a probability score between 0 and 1 (0 and 100%).
0.23 Probability of exploitation activity being observed over the next 30 days (14th percentile)
CVSS score for CVE-2026-93633
CVSS (Common Vulnerability Scoring System): An open framework owned and managed by FIRST.Org, Inc. that assigns a numerical score from 0 to 10 to software vulnerabilities to indicate their severity.
5.4 Medium
Products affected by CVE-2026-93633
Zimbra Collaboration Suite 8.6.0
Zimbra Collaboration Suite 8.7.11
Zimbra Collaboration Suite 8.8.10
Zimbra Collaboration Suite 8.8.11
Zimbra Collaboration Suite 8.8.12
DVE Score by Bitsight AI
DVE scores complement traditional static scoring systems like CVSS with Bitsight AI powered real-time threat intelligence and underground cyber criminal activity so that security teams can reduce alert fatigue and focus on vulnerabilities most likely to be exploited.
Low
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CVE-2026-93633 Global Footprint

Top 10 Identified Countries

Country Observations Percentage
US 66 9.12%
ID 54 7.46%
BR 54 7.46%
VN 38 5.25%
CA 31 4.28%
DE 29 4.01%
FR 28 3.87%
IN 25 3.45%
TR 23 3.18%
IT 22 3.04%

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CVE-2026-93633 Industry Footprint

Top 10 Identified Industries

*Service provider organizations (typically Technology and Telecommunications) are disproportionally represented in the results given their upstream ownership of end-user infrastructure. See our FAQs.

Industry* Observations Percentage
Technology 178 46.72%
Telecommunications 162 42.52%
Government/Politics 12 3.15%
Business Services 7 1.84%
Education 5 1.31%
Finance 4 1.05%
Food Production 3 0.79%
Manufacturing 2 0.52%
Engineering 2 0.52%
Transportation 2 0.52%

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