CVE-2026-55123 Microsoft CVE debrief

Who should care

Users of Microsoft Office PowerPoint, particularly those using versions 2016, 2019, 2021, and 2024, should be aware of this vulnerability and take necessary precautions. IT administrators and security teams should prioritize patching vulnerable versions of Microsoft Office PowerPoint and implement compensating controls to mitigate the risk.

Technical summary

A heap-based buffer overflow vulnerability exists in Microsoft Office PowerPoint, which allows an unauthorized attacker to execute code locally. The vulnerability is caused by improper handling of certain input data, leading to a buffer overflow condition. This vulnerability affects various versions of Microsoft Office, including Office 2016, 2019, 2021, and 2024. Users should be cautious when opening PowerPoint files from untrusted sources.

Defensive priority

High priority should be given to patching vulnerable versions of Microsoft Office PowerPoint, as this vulnerability allows for local code execution.

Recommended defensive actions

• Apply patches or updates provided by Microsoft to vulnerable versions of Microsoft Office PowerPoint
• Ensure that all users have the latest versions of Microsoft Office installed
• Implement compensating controls, such as restricting access to sensitive data and monitoring for suspicious activity
• Conduct regular vulnerability assessments and penetration testing to identify potential weaknesses
• Review compensating controls for exposed systems while remediation is scheduled and verified

Evidence notes

The CVE record and NVD detail provide information on the vulnerability, including its description, CVSS score, and affected products. The vendor advisory and patch information are also available. However, the scope of affected products and versions is limited, and defenders should verify the information with Microsoft. The CVE record was published on 2026-07-14T18:18:18.633Z and has not been modified since then.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.