Description
An authentication rate-limit bypass in Zimbra Collaboration Suite 10.1.0 through 10.1.21 allows unauthenticated attackers to make repeated password guesses through GraphQL without incrementing Zimbra’s source-IP failure counter. GraphQL aliases allow multiple authentication attempts in one HTTP request.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Zimbra | Zimbra Collaboration Suite | ≤ 10.1.21 | — |
Advisories 1
- WID-SEC-2026-3977 Synacor Zimbra: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 14, 2026
References
- https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1 third-party-advisory