Local disclosure via improper input validation
Published Aug 11, 2026 · Updated Aug 25, 2026
Improper input validation in Microsoft Office Excel allows attackers to read sensitive information locally by opening a crafted document. Microsoft has not published the affected parser or field, only that Excel mishandles untrusted document data during validation and can expose confidential data from the local processing context. Exploitation requires user interaction on the local system, and published scoring bounds the impact to confidentiality rather than code execution, tampering, or service interruption.
Summary
What happened
Improper input validation in Microsoft Office Excel allows attackers to read sensitive information locally by opening a crafted document. Microsoft has not published the affected parser or field, only that Excel mishandles untrusted document data during validation and can expose confidential data from the local processing context. Exploitation requires user interaction on the local system, and published scoring bounds the impact to confidentiality rather than code execution, tampering, or service interruption.
The record
- CVE
- CVE-2026-70318
- Published
- Aug 11, 2026
- Updated
- Aug 25, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-20, 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.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
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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