# CVE-2026-93637: Zimbra Collaboration Suite GraphQL Batched Authentication Bypasses Pre-Auth Rate Limiting

> Unauthenticated attackers can bypass pre-authentication rate limits in Zimbra Collaboration Suite by using GraphQL aliases to perform repeated password guessing.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Oct 2026
- **Updated:** 16 Oct 2026
- **Also known as:** GHSA-gm33-c835-gc8h

## What is CVE-2026-93637?

CVE-2026-93637 is a low-severity vulnerability in Zimbra Collaboration Suite, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2026-93637?


## How do I fix CVE-2026-93637?

No fix has been published for CVE-2026-93637 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-93637 being exploited?

There is no known exploitation of CVE-2026-93637 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93637 and fix it if it is affected.

What it is: CVE-2026-93637 is a low-severity vulnerability in Zimbra Collaboration Suite, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-93637 in the wild and no public exploit code.

Affected product: Zimbra Collaboration Suite. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-93637/ (Markdown: https://insights.sbomify.com/CVE-2026-93637/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93637
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93637
- OSV: https://osv.dev/vulnerability/CVE-2026-93637

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-93637/
Summaries are generated and may contain mistakes; the official description above is the record.