Remote certificate spoofing via improper validation
Published Jul 14, 2021 · Updated Aug 10, 2026
Certificate spoofing in Microsoft Windows versions listed for CVE-2021-34492 allows remote attackers to bypass certificate validation and gain confidentiality and integrity impact via crafted network traffic. The certificate verification path accepts an improperly constructed certificate chain, allowing a man-in-the-middle attacker to present a certificate that Windows treats as trusted. Exploitation requires user interaction with the attacker-controlled connection; availability is not affected.
Summary
What happened
Certificate spoofing in Microsoft Windows versions listed for CVE-2021-34492 allows remote attackers to bypass certificate validation and gain confidentiality and integrity impact via crafted network traffic. The certificate verification path accepts an improperly constructed certificate chain, allowing a man-in-the-middle attacker to present a certificate that Windows treats as trusted. Exploitation requires user interaction with the attacker-controlled connection; availability is not affected.
The record
- CVE
- CVE-2021-34492
- Published
- Jul 14, 2021
- Updated
- Aug 10, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 14, 2021CVE publishedPublication date reported by the CVE source.
- Aug 10, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.10240.0 <10.0.10240.19003
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Reported exploitation
- CISA Known Exploited Vulnerabilities catalog listingknown exploited catalog
Technologies
Your stack
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Your stack
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