A reflected cross-site scripting vulnerability in the login page of Zimbra Collaboration Suite (ZCS) allows an unauthenticated attacker to execute JavaScript through the zrememberme parameter. A crafted relogin URL selects a two-factor error display that inserts the parameter into a hidden input attribute without HTML encoding. A victim who opens the URL receives attacker-controlled script and page content under the legitimate Zimbra origin, allowing credential capture through a replacement login form. The relogin path logs out an existing session before rendering the payload, so the demonstrated attack does not inherit that session's mailbox access. ZCS 10.1.16 and 10.1.17 are affected.
References
| Link | Resource |
|---|---|
| https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories | Vendor Advisory |
| https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ | Exploit Third Party Advisory |
Configurations
History
28 Oct 2026, 21:13
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Synacor zimbra Collaboration Suite
Synacor |
|
| CPE | cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:* | |
| References | () https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories - Vendor Advisory | |
| References | () https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ - Exploit, Third Party Advisory |
23 Oct 2026, 14:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-10-23 14:17
Updated : 2026-10-28 21:13
NVD link : CVE-2026-93638
Mitre link : CVE-2026-93638
CVE.ORG link : CVE-2026-93638
JSON object : View
Products Affected
synacor
- zimbra_collaboration_suite
CWE
CWE-79
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')