Code execution via undisclosed integer underflow
Published Jun 9, 2026 · Updated Jun 9, 2026
Integer underflow in Microsoft Excel allows attackers to execute code when a user opens a crafted workbook on an affected Office installation. Microsoft identifies an integer wraparound in Excel but has not disclosed the affected parser, data field, or arithmetic operation. Exploitation requires user interaction, and successful code runs in the user's security context with the ability to read, alter, or interrupt accessible resources.
Summary
What happened
Integer underflow in Microsoft Excel allows attackers to execute code when a user opens a crafted workbook on an affected Office installation. Microsoft identifies an integer wraparound in Excel but has not disclosed the affected parser, data field, or arithmetic operation. Exploitation requires user interaction, and successful code runs in the user's security context with the ability to read, alter, or interrupt accessible resources.
The record
- CVE
- CVE-2026-44817
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- Microsoft
- Product
- Microsoft Office LTSC for Mac 2024
- Classifications
- CWE-843, T1204.002, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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