Kernel memory disclosure via out-of-bounds read
Published Feb 14, 2023 · Updated Aug 19, 2026
An out-of-bounds read in HTTP.sys in affected Microsoft Windows builds allows local users to disclose kernel memory via unspecified input. HTTP.sys reads beyond an allocated buffer and exposes adjacent memory, but Microsoft has not published the affected routine or malformed input that triggers the read. Exploitation requires local low-privileged access and yields confidentiality loss without reported integrity or availability impact.
Summary
What happened
An out-of-bounds read in HTTP.sys in affected Microsoft Windows builds allows local users to disclose kernel memory via unspecified input. HTTP.sys reads beyond an allocated buffer and exposes adjacent memory, but Microsoft has not published the affected routine or malformed input that triggers the read. Exploitation requires local low-privileged access and yields confidentiality loss without reported integrity or availability impact.
The record
- CVE
- CVE-2023-21687
- Published
- Feb 14, 2023
- Updated
- Aug 19, 2026
- Vendor
- Microsoft
- Product
- Windows 11 version 21H2
- Classifications
- CWE-125
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 14, 2023CVE publishedPublication date reported by the CVE source.
- Aug 19, 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=10.0.0 <10.0.22621.1574
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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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Technologies
Your stack
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Your stack
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