XSS in Synacor Zimbra Collaboration Suite
CVE-2026-33368
Zimbra Collaboration Suite (ZCS) 10.0 and 10.1 contains a reflected cross-site scripting (XSS) vulnerability in the Classic Webmail REST interface (/h/rest). The application fails to properly sanitize user-supplied input, allowing an unauthenticated attacker to inject malicious JavaScript into a crafted URL. When a victim user accesses the link, the injected script executes in the context of the Zimbra webmail application, which could allow the attacker to perform actions on behalf of the victim.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.002 (13.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Synacor Zimbra_collaboration_suite
- N/a — versions n/a
Weakness classification (CWE)
References
- cve@mitre.org (Vendor Advisory)
- cve@mitre.org (Release Notes, Vendor Advisory)
- cve@mitre.org (Product)
- cve@mitre.org (Release Notes)
Frequently asked questions
- What is CVE-2026-33368?
- CVE-2026-33368 is a medium-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-03-20.
- How severe is CVE-2026-33368?
- Medium severity. CVSS v3 base score is 6.1 out of 10.