CVE-2025-66376 — Synacor Zimbra Collaboration Suite (ZCS): Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability
CVE-2025-66376 — Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability in the Classic UI where attackers could abuse Cascading Style Sheets (CSS) @import directives in email HTML.
What This Means For You
- CISA has confirmed active exploitation — immediate patching required.
- Added to CISA KEV catalog — federal agencies must remediate by 2026-04-01.
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2025-66376 | XSS | Synacor Zimbra Collaboration Suite (ZCS) Classic UI, abuse of CSS @import directives in email HTML |
Source & Attribution
| Source Platform | CISA |
| Channel | CISA KEV |
| Published | March 18, 2026 at 14:00 UTC |
This content was curated and summarized by Shimi's Cyber World for informational purposes. It is not copied or republished in full. All intellectual property rights remain with the original author and source.
Believe this infringes your rights? Submit a takedown request.
Related coverage
CVE-2026-20240 — Denial of Service
CVE-2026-20240 — In Splunk Enterprise versions below 10.2.2, 10.0.5, 9.4.11, and 9.3.12, and Splunk Cloud Platform versions below 10.4.2603.1, 10.3.2512.9, 10.2.2510.11, 10.1.2507.21, 10.0.2503.13, and 9.3.2411.129,...
Splunk Enterprise, Cloud Vulnerability Exposes Session Cookies, Sensitive Data
CVE-2026-20239 — In Splunk Enterprise versions below 10.2.2 and 10.0.5, and Splunk Cloud Platform versions below 10.3.2512.8, 10.2.2510.11, 10.1.2507.21, and 10.0.2503.13, a user with a...
CVE-2026-20238 — In Splunk AI Toolkit versions below 5.7.3, a low-privileged
CVE-2026-20238 — In Splunk AI Toolkit versions below 5.7.3, a low-privileged user that does not hold the 'admin' or 'power' roles could access confidential data...