---
id: CVE-2026-93637
title: >-
  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
summary: >-
  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 …
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-307
vendor: Zimbra
product: Zimbra Collaboration Suite
affected:
  - collaboration_suite <= 10.1.21
published: '2026-10-14'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:55:59.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93637'
references:
  - url: >-
      https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1
    label: cve@rapid7.com
tags:
  - nvd
  - cve.org
epss: 0.00325
epssPercentile: 0.25408
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-16T15:18:20.000158Z'
ingestedAt: '2026-10-14T17:44:53.680Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.