๐Ÿ” CVE Alert

CVE-2026-93638

MEDIUM 6.1

Zimbra Collaboration Suite Pre-Authentication Reflected Cross-Site Scripting via Login Page zrememberme Parameter

CVSS Score
6.1
EPSS Score
0.0%
EPSS Percentile
0th

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.

CWE CWE-79
Vendor zimbra
Product zimbra collaboration suite
Published Oct 23, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

Affected Versions

Zimbra / Zimbra Collaboration Suite
0 โ‰ค 10.1.17

References

NVD โ†— CVE.org โ†— EPSS Data โ†—
wiki.zimbra.com: https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories rapid7.com: https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/

Credits

Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7