# CVE-2016-3999: Zimbra Collaboration multiple XSS vulnerabilities

Source: https://junglewise.ai/threats/cve-2016-3999-zimbra-collaboration-multiple-xss-vulnerabilities  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2017-01-18. Updated: 2026-05-13  
License: CC BY 4.0 with a link back

CVE-2016-3999 · Severity: medium · CVSS 6.1 · Published 2017-01-18

Zimbra Collaboration is a widely used enterprise email and collaboration platform. Multiple vulnerabilities in versions prior to 8.7.0 allow remote attackers to inject malicious scripts into the web interface. If a user views a specially crafted page or email, an attacker could potentially steal login credentials, hijack user sessions, or perform actions on behalf of the user.

Technologies: [Synacor Zimbra Collaboration Suite](https://junglewise.ai/threats/technologies/zimbra-collaboration-suite), [Zimbra Collaboration Suite](https://junglewise.ai/threats/technologies/collaboration). Vendors: [Synacor](https://junglewise.ai/threats/vendors/synacor), [Zimbra](https://junglewise.ai/threats/vendors/zimbra).

## Quick answers

**Is CVE-2016-3999 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2016-3999 being exploited in the wild.

**How severe is CVE-2016-3999?** Medium severity, with a CVSS score of 6.1, published 18 January 2017.

**Which products and versions are affected?** Zimbra Collaboration Suite before 8.7.0.

**Is there a fix for CVE-2016-3999?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2016-3999 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2016-3999?** Check whether you run Synacor Zimbra Collaboration Suite or Zimbra Collaboration Suite at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

Multiple cross-site scripting (XSS) vulnerabilities exist in Zimbra Collaboration Suite (ZCS) prior to version 8.7.0. The flaws, identified internally as bugs 104552 and 104703, stem from improper neutralization of user-supplied input during web page generation (CWE-79). A remote, unauthenticated attacker can exploit these vulnerabilities by enticing a user to interact with a malicious link or view crafted content, leading to the execution of arbitrary JavaScript in the context of the victim's browser session. This can result in session hijacking or unauthorized access to sensitive user data. The issues are resolved in Zimbra Collaboration 8.7.0.

## Affected products

- Zimbra Zimbra Collaboration Suite before 8.7.0

## Timeline

- 2016-03-31: disclosed: CVE assigned
- 2017-01-18: advisory: NVD publication date

## References

- [http://www.securityfocus.com/bid/95921](http://www.securityfocus.com/bid/95921)
- [https://wiki.zimbra.com/wiki/Zimbra_Releases/8.7.0](https://wiki.zimbra.com/wiki/Zimbra_Releases/8.7.0)
- [https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories](https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories)

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- [Zimbra Collaboration Suite authorization bypass in Zimlet configuration](https://junglewise.ai/threats/cve-2026-93639-a-missing-authorization-vulnerability-in-zimbra-collaboration)
- [Zimbra Collaboration Suite reflected cross-site scripting in login](https://junglewise.ai/threats/cve-2026-93638-a-reflected-cross-site-scripting-vulnerability-in-the-login-page)
- [Zimbra Collaboration Suite LDAP filter injection](https://junglewise.ai/threats/cve-2026-93636-an-ldap-filter-injection-vulnerability-in-zimbra-collaboration)
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