# CVE-2016-3378: Microsoft Exchange Open Redirect Vulnerability

CVE-2016-3378 is fixed in 5 products on 1 platform, first by KB3184736, released September 13, 2016. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2016-3378
- Priority: Routine
- CVSS: n/a (Moderate)
- EPSS: 0.1528
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Unlikely
- Published: Sep 13, 2016
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2016-3378

## Description

<p>An open redirect vulnerability exists in Microsoft Exchange that could lead to spoofing.</p> <p>To exploit the vulnerability, an attacker could send a link that has a specially crafted URL, and convince the user to click the link. When an authenticated Exchange user clicks the link, the authenticated user's browser session could be redirected to a malicious site that is designed to impersonate a legitimate website. By doing so, the attacker could trick the user and potentially acquire sensitive information, such as the user's credentials.</p> <p>The update addresses the vulnerability by correcting how Exchange handles open redirect requests.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Microsoft Exchange Server 2013 Cumulative Update 12 |  | [KB3184736](https://patchblox.com/security/data/fix/microsoft/kb3184736.md) | Sep 13, 2016 |
| Microsoft | Microsoft Exchange Server 2013 Cumulative Update 13 |  | [KB3184736](https://patchblox.com/security/data/fix/microsoft/kb3184736.md) | Sep 13, 2016 |
| Microsoft | Microsoft Exchange Server 2013 Service Pack 1 |  | [KB3184736](https://patchblox.com/security/data/fix/microsoft/kb3184736.md) | Sep 13, 2016 |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 1 |  | [KB3184736](https://patchblox.com/security/data/fix/microsoft/kb3184736.md) | Sep 13, 2016 |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 2 |  | [KB3184736](https://patchblox.com/security/data/fix/microsoft/kb3184736.md) | Sep 13, 2016 |

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Data as of 2026-11-07T06:34:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo