Information disclosure via long IPv6 scope identifier
Published Jan 14, 2025 · Updated Jun 9, 2026
Security-feature bypass in Microsoft Windows allows remote attackers to disclose information through a crafted UNC path with user interaction. MapUrlToZone percent-encodes an overlong IPv6 scope identifier, then fails IPv6 parsing and treats the address as a dotless DNS name in the Intranet zone. Exploitation requires a crafted remote-share path, a valid scope identifier for the target, and user interaction; the demonstrated consequence is unintended remote-resource access with limited confidentiality loss.
Summary
What happened
Security-feature bypass in Microsoft Windows allows remote attackers to disclose information through a crafted UNC path with user interaction. MapUrlToZone percent-encodes an overlong IPv6 scope identifier, then fails IPv6 parsing and treats the address as a dotless DNS name in the Intranet zone. Exploitation requires a crafted remote-share path, a valid scope identifier for the target, and user interaction; the demonstrated consequence is unintended remote-resource access with limited confidentiality loss.
The record
- CVE
- CVE-2025-21328
- Published
- Jan 14, 2025
- Updated
- Jun 9, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- CWE-41, T1204
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 14, 2025CVE 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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Is a vulnerable build present?
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- Affected versionversion=10.0.10240.0 <10.0.10240.20890
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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Public exploit references
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Technologies
Your stack
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Your stack
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