# CVE-2019-9670: Synacor Zimbra Collaboration Suite (ZCS) Improper Restriction of XML External Entity Reference

> An XML External Entity injection vulnerability in Zimbra's mailboxd component allows attackers to read sensitive files or cause denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 10 Jan 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 May 2019
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-pj74-pf28-5qjw

## What is CVE-2019-9670?

CVE-2019-9670 is a critical vulnerability in Synacor Zimbra Collaboration Suite, published on 29 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

mailboxd component in Synacor Zimbra Collaboration Suite 8.7.x before 8.7.11p10 has an XML External Entity injection (XXE) vulnerability, as demonstrated by Autodiscover/Autodiscover.xml.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2019-9670?

It affects 1 product.


Products: Synacor Zimbra Collaboration Suite.

## How do I fix CVE-2019-9670?

No fix has been published for CVE-2019-9670 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 10 Jul 2022.

## Is CVE-2019-9670 being exploited?

Yes. Attackers have exploited CVE-2019-9670 in the wild since at least 10 Jan 2022.

Public exploit code:

- Zimbra RCE PoC - CVE-2019-9670 XXE/SSRF (github_poc): https://github.com/rek7/Zimbra-RCE
- Zimbra RCE CVE-2019-9670 (github_poc): https://github.com/attackgithub/Zimbra-RCE
- Zimbra Collaboration Autodiscover Servlet XXE and ProxyServlet SSRF (metasploit)
- Zimbra Collaboration - Autodiscover Servlet XXE and ProxyServlet SSRF (Metasploit) (exploitdb)
- Zimbra Collaboration - Autodiscover Servlet XXE and ProxyServlet SSRF (Metasploit) (exploitdb)
- Zimbra Collaboration - Autodiscover Servlet XXE and ProxyServlet SSRF (Metasploit) (exploitdb)

## Other vulnerabilities in Synacor Zimbra Collaboration Suite

- [CVE-2024-45519](https://insights.sbomify.com/CVE-2024-45519/): Synacor Zimbra Collaboration Suite (ZCS) Command Execution (critical 10.0, exploited in the wild)
- [CVE-2022-41352](https://insights.sbomify.com/CVE-2022-41352/): Synacor Zimbra Collaboration Suite (ZCS) Arbitrary File Upload (critical 9.8, exploited in the wild)
- [CVE-2022-37042](https://insights.sbomify.com/CVE-2022-37042/): Synacor Zimbra Collaboration Suite (ZCS) Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2022-27924](https://insights.sbomify.com/CVE-2022-27924/): Synacor Zimbra Collaboration Suite (ZCS) Command Injection (critical 9.8, exploited in the wild)
- [CVE-2020-7796](https://insights.sbomify.com/CVE-2020-7796/): Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-9670 and fix it if it is affected.

What it is: CVE-2019-9670 is a critical vulnerability in Synacor Zimbra Collaboration Suite, published on 29 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2019-9670 in the wild since at least 10 Jan 2022.

Affected product: Synacor 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-2019-9670/ (Markdown: https://insights.sbomify.com/CVE-2019-9670/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-9670
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-9670
- OSV: https://osv.dev/vulnerability/CVE-2019-9670

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-9670/
Summaries are generated and may contain mistakes; the official description above is the record.