# CVE-2018-8302: Microsoft Exchange Memory Corruption Vulnerability

CVE-2018-8302 is fixed in 5 products on 1 platform, first by KB4340733, released August 14, 2018. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2018-8302
- Priority: Urgent
- CVSS: n/a (Critical)
- EPSS: 0.2707
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Aug 14, 2018
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2018-8302

## Description

<p>A remote code execution vulnerability exists in Microsoft Exchange software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the System user. An attacker could then install programs; view, change, or delete data; or create new accounts.</p> <p>Exploitation of the vulnerability requires that a specially crafted email be sent to a vulnerable Exchange server.</p> <p>The security update addresses the vulnerability by correcting how Microsoft Exchange handles objects in memory.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Microsoft Exchange Server 2010 Service Pack 3 Update Rollup 23 |  | [KB4340733](https://patchblox.com/security/data/fix/microsoft/kb4340733.md) | Aug 14, 2018 |
| Microsoft | Microsoft Exchange Server 2013 Cumulative Update 20 |  | [KB4340731](https://patchblox.com/security/data/fix/microsoft/kb4340731.md) | Aug 14, 2018 |
| Microsoft | Microsoft Exchange Server 2013 Cumulative Update 21 |  | [KB4340731](https://patchblox.com/security/data/fix/microsoft/kb4340731.md) | Aug 14, 2018 |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 10 |  | [KB4340731](https://patchblox.com/security/data/fix/microsoft/kb4340731.md) | Aug 14, 2018 |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 9 |  | [KB4340731](https://patchblox.com/security/data/fix/microsoft/kb4340731.md) | Aug 14, 2018 |

---

Data as of 2026-11-12T13:55:20Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.