Cross-site scripting in Zimbra Collaboration
Priority CRITICAL 89Exploited in the wildCWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
Zimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows Classic UI stored XSS via Cascading Style Sheets (CSS) @import directives in an HTML e-mail message.
Why it matters now
Exploitation Active In CISA KEV since 2026-03-18CISA due date 2026-04-01
EPSS 0.20227 97th percentileScored 2026-11-07
Fix Fixed Collaboration (Zimbra): 10.0.18, 10.1.13
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Active
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Zimbra | Collaboration | 10.0 to before 10.0.18; 10.1 to before 10.1.13 | 10.0.18, 10.1.13 | Patch available | CNA |
- Collaboration VendorZimbra Affected 10.0 to before 10.0.18; 10.1 to before 10.1.13 Fixed in 10.0.18, 10.1.13 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:* | 10.0.0 to before 10.0.18; 10.1.0 to before 10.1.13 | Vulnerable | Synacor |
- cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:* Versions 10.0.0 to before 10.0.18; 10.1.0 to before 10.1.13 Vulnerable ·Synacor
Remediation
- Fix · CNA Collaboration (Zimbra) Fixed in 10.0.18, 10.1.13
Timeline
- 2026-03-18 Added to CISA KEV
- 2026-10-02 Threatist record created from CVE-2025-66376
- 2026-10-03 Alias added: GHSA-h7wg-85fj-3c6g
References
Advisory 2
More Zimbra vulnerabilities
- TI-2026-51660 OS command injection in Zimbra Collaboration KEVCVSS 3.1HIGH 8.9
- TI-2024-18266 An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. KEVCVSS 3.1MEDIUM 6.1
- TI-2024-30553 An issue was discovered in Zimbra Collaboration (ZCS) 10.1.x before 10.1.1, 10.0.x before… CVSS 3.1HIGH 8.8
- TI-2022-13998 Zimbra Collaboration Open Source 8.8.15 does not encrypt the initial-login randomly… CVSS 3.1CRITICAL 9.8
- TI-2026-63080 Path traversal in Zimbra Collaboration Suite CVSS 3.1CRITICAL 9.8
- TI-2023-13772 An issue in Zimbra Collaboration ZCS v.8.8.15 and v.9.0 allows an attacker to execute… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2025-66376 · CVE Program
- CVE-2025-66376 · NVD
- CISA Known Exploited Vulnerabilities
- FIRST EPSS
- GHSA-h7wg-85fj-3c6g · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences