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Vulnerability record · public intelligence
CVE-2026-21240
HIGH
Windows HTTP.sys Elevation of Privilege Vulnerability
Published Feb 10, 2026 · Updated Nov 3, 2026
Severity · CVSSHIGH · Not scored
Known exploitationNot listed
EPSS / likelihood0.28%
QFinch risk scoreNot available
Original summary
Normalized public record · Updated Nov 3, 2026
Windows HTTP.sys Elevation of Privilege Vulnerability
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
Time-of-check time-of-use (toctou) race condition in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
FIRST-EPSSCVE-LIST-V5
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Feb 10, 2026 · Last refreshed Nov 3, 2026