CVE-2026-21259
Analyzed
Analyzed - Analysis Complete
Heap-Based Buffer Overflow in Excel Enables Local Privilege Escalation
Publication date: 2026-02-10
Last updated on: 2026-02-11
Assigner: Microsoft Corporation
Description
Description
Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to elevate privileges locally.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| microsoft | 365_apps | * |
| microsoft | 365_apps | * |
| microsoft | excel | 2016 |
| microsoft | excel | 2016 |
| microsoft | office | 2019 |
| microsoft | office | 2019 |
| microsoft | office_long_term_servicing_channel | 2021 |
| microsoft | office_long_term_servicing_channel | 2021 |
| microsoft | office_long_term_servicing_channel | 2024 |
| microsoft | office_long_term_servicing_channel | 2024 |
| microsoft | office_online_server | to 16.0.10417.20097 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-787 | The product writes data past the end, or before the beginning, of the intended buffer. |
| CWE-122 | A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). |
