Local memory disclosure via off-by-one read
Published Aug 11, 2026 · Updated Aug 25, 2026
Off-by-one error in Microsoft Office Word allows local users to read sensitive memory via a crafted document opened in Word. Microsoft has described the flaw only as an off-by-one error; public records do not identify the parser or function, but the paired CWE-125 mapping indicates a one-element out-of-bounds read on Word-controlled input. Exploitation requires local delivery and user interaction to open the malicious file, and the published scoring bounds the impact to confidentiality rather than code execution or document modification.
Summary
What happened
Off-by-one error in Microsoft Office Word allows local users to read sensitive memory via a crafted document opened in Word. Microsoft has described the flaw only as an off-by-one error; public records do not identify the parser or function, but the paired CWE-125 mapping indicates a one-element out-of-bounds read on Word-controlled input. Exploitation requires local delivery and user interaction to open the malicious file, and the published scoring bounds the impact to confidentiality rather than code execution or document modification.
The record
- CVE
- CVE-2026-66806
- Published
- Aug 11, 2026
- Updated
- Aug 25, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-125, CWE-193, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 11, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 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?
Affected products and versions are unavailable in this record.
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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