Code execution via unchecked WebCharts array index
Published Jun 13, 2023 · Updated Nov 4, 2025
Heap-based buffer overflow in Microsoft Excel allows context-dependent attackers to execute code when a user opens a malformed file. The WebCharts parser uses an attacker-controlled element index without checking the fixed array's capacity, then clears the calculated slot with memset outside the allocation. Exploitation requires user interaction and can run code in the affected Office process; malformed input can instead crash Excel.
Summary
What happened
Heap-based buffer overflow in Microsoft Excel allows context-dependent attackers to execute code when a user opens a malformed file. The WebCharts parser uses an attacker-controlled element index without checking the fixed array's capacity, then clears the calculated slot with memset outside the allocation. Exploitation requires user interaction and can run code in the affected Office process; malformed input can instead crash Excel.
The record
- CVE
- CVE-2023-33133
- Published
- Jun 13, 2023
- Updated
- Nov 4, 2025
- Vendor
- Microsoft
- Product
- Microsoft Office 2019
- Classifications
- CWE-122, CWE-787, T1204.002, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 13, 2023CVE publishedPublication date reported by the CVE source.
- Nov 4, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=19.0.0 <https://aka.ms/OfficeSecurityReleases
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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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