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CVE-2026-55033 Microsoft CVE debrief

CVE-2026-55033 is an integer overflow or wraparound vulnerability in Microsoft Office Word, classified as HIGH severity with a CVSS score of 7.8. The vulnerability allows an unauthorized attacker to execute code locally. It was published on 2026-07-14T18:18:14.293Z and last modified on 2026-07-16T16:13:17.387Z. The vulnerability exists due to improper handling of integer values in Microsoft Office Word, which can lead to code execution. Users of Microsoft Office Word, particularly those using Microsoft 365 Apps, Office 2019, Office 2021, and Office 2024, should be aware of this vulnerability and take necessary precautions.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-16
Advisory published
2026-07-14
Advisory updated
2026-07-16

Who should care

Users of Microsoft Office Word, particularly those using Microsoft 365 Apps, Office 2019, Office 2021, and Office 2024, should be aware of this vulnerability. IT administrators, security teams, and operators using these products should prioritize patching and implement compensating controls to mitigate potential risks. Vulnerability management and security teams should review the CVE record and NVD entry for accurate mitigation and exposure assessment.

Technical summary

The vulnerability exists in Microsoft Office Word due to an integer overflow or wraparound, allowing an unauthorized attacker to execute code locally. The CVSS vector is CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. This vulnerability can be exploited through a malicious file or link, highlighting the need for careful handling of Office documents. Microsoft Office Word's handling of integer values is flawed, leading to potential code execution.

Defensive priority

High priority should be given to patching vulnerable systems, especially those with high-risk exposure. Implementing compensating controls such as monitoring for suspicious activity and conducting regular vulnerability assessments is also crucial.

Recommended defensive actions

  • Apply patches provided by Microsoft
  • Ensure all users have the latest version of Microsoft Office Word
  • Implement compensating controls such as monitoring for suspicious activity
  • Conduct regular vulnerability assessments
  • Review and update asset inventory to identify exposed systems

Evidence notes

The CVE record was published on 2026-07-14T18:18:14.293Z and was last modified on 2026-07-16T16:13:17.387Z. The NVD entry is currently Analyzed. The vulnerability has been confirmed in Microsoft Office Word, with a CVSS score of 7.8 and classified as HIGH severity. Evidence from the CVE record and NVD entry indicates that an integer overflow or wraparound vulnerability exists, allowing an unauthorized attacker to execute code locally. However, the exact scope of affected products and versions is limited in the provided sources. Defenders should verify the affected scope and vendor guidance for accurate mitigation.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-14T18:18:14.293Z and has not been modified since then. The NVD entry is currently Analyzed.