# CVE-2026-55123: Microsoft PowerPoint heap overflow in numeric type conversion Source: https://junglewise.ai/threats/cve-2026-55123-microsoft-powerpoint-heap-overflow-in-numeric-type-conversion Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats Published: 2026-07-14. Updated: 2026-07-14 License: CC BY 4.0 with a link back CVE-2026-55123 · Severity: high · CVSS 7.8 · Published 2026-07-14 Microsoft PowerPoint is a widely used presentation software. A vulnerability in how it handles certain data could allow an attacker to take control of a user's computer if the user is tricked into opening a malicious presentation file. This could lead to the theft of sensitive information, installation of malware, or disruption of business operations. Technologies: [Microsoft 365 Apps for Enterprise](https://junglewise.ai/threats/technologies/365-apps-for-enterprise), [Microsoft Office 2019](https://junglewise.ai/threats/technologies/office-2019), [Microsoft Office 365 for Mac](https://junglewise.ai/threats/technologies/office-365-for-mac), [Microsoft Office LTSC 2021](https://junglewise.ai/threats/technologies/office-ltsc-2021), [Microsoft Office LTSC 2024](https://junglewise.ai/threats/technologies/office-ltsc-2024), [Microsoft Office LTSC for Mac 2021](https://junglewise.ai/threats/technologies/office-ltsc-for-mac-2021), [Microsoft Office LTSC for Mac 2024](https://junglewise.ai/threats/technologies/office-ltsc-for-mac-2024), [Microsoft PowerPoint 2016](https://junglewise.ai/threats/technologies/powerpoint-2016). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft). ## Quick answers **Is CVE-2026-55123 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55123 being exploited in the wild. **How severe is CVE-2026-55123?** High severity, with a CVSS score of 7.8, published 14 July 2026. **Which products and versions are affected?** Microsoft 365 Apps for Enterprise 16.0.1 and later versions prior to security release; Microsoft Office 2019 19.0.0 and later versions prior to security release; Microsoft Office 365 for Mac 1.0.0 to 16.111.26071215; Microsoft Office LTSC 2021 16.0.1 and later versions prior to security release; and 4 more. **Is there a fix for CVE-2026-55123?** 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-2026-55123 attacked?** It is attacked with local access, in a network appliance. **Am I affected by CVE-2026-55123?** Check whether you run Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office 365 for Mac or one of the others listed 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 A heap-based buffer overflow vulnerability exists in Microsoft Office PowerPoint due to incorrect conversion between numeric types (CWE-681) and improper memory management (CWE-122). The vulnerability is triggered when the application processes a specially crafted PowerPoint file. An attacker can exploit this by convincing a user to open a malicious file, leading to arbitrary code execution in the context of the current user. The attack vector is local, requiring user interaction (UI:R). Microsoft has released security updates to address this issue across various versions of Office and PowerPoint. ## Affected products - Microsoft Microsoft 365 Apps for Enterprise 16.0.1 and later versions prior to security release - Microsoft Microsoft Office 2019 19.0.0 and later versions prior to security release - Microsoft Microsoft Office 365 for Mac 1.0.0 to 16.111.26071215 - Microsoft Microsoft Office LTSC 2021 16.0.1 and later versions prior to security release - Microsoft Microsoft Office LTSC 2024 16.0.0 and later versions prior to security release - Microsoft Microsoft Office LTSC for Mac 2021 16.0.1 to 16.111.26071215 - Microsoft Microsoft Office LTSC for Mac 2024 16.0.0 to 16.111.26071215 - Microsoft Microsoft PowerPoint 2016 16.0.0 to 16.0.5561.1000 ## Timeline - 2026-07-14: disclosed: Initial publication of the CVE record - 2026-07-14: advisory: Microsoft released security update guide information ## References - [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55123](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55123) ## Related threats - [Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information locally.](https://junglewise.ai/threats/cve-2026-70310-out-of-bounds-read-in-microsoft-office-word-allows-an) - [Microsoft Office out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-56195-microsoft-office-out-of-bounds-read-information-disclosure) - [Microsoft Office Out-of-bounds Read Information Disclosure](https://junglewise.ai/threats/cve-2026-56192-microsoft-office-out-of-bounds-read-information-disclosure) - [Microsoft Office Excel heap buffer overflow](https://junglewise.ai/threats/cve-2026-56156-microsoft-office-excel-heap-buffer-overflow) - [Microsoft Excel use of uninitialized resource code execution](https://junglewise.ai/threats/cve-2026-55949-microsoft-excel-use-of-uninitialized-resource-code-execution)