CVE-2026-42899: Microsoft Security Advisory CVE-2026-42899 – ASP.NET Core Denial of Service Vulnerability

Executive Summary: Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 8.0, .NET 9.0, and .NET 10.0. This advisory also provides guidance on what developers can do to updat…

7.5CVSS Score

HIGHSeverity

NOCISA KEV

VulnerabilityImpact Type

📋 Vulnerability Details

CVE ID	CVE-2026-42899
Vendor	nuget
Affected Product	Microsoft.AspNetCore.App.Runtime.win-arm
Vulnerability Type	Vulnerability
CVSS Score	7.5 (HIGH)
Actively Exploited	❌ No known exploitation
Patch Status	See Vendor Advisory →
Reported By	CYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories)

🔬 Technical Analysis

Executive Summary: Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 8.0, .NET 9.0, and .NET 10.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. Loop with unreachable exit condition ('infinite loop') in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/397

CVSS Details - Version: 3.1

• Severity: - Score: 7.5

• Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')

Affected Platforms - Platforms: All

• Architectures: All #

🎯 Known Indicators of Compromise

{"type":"url","value":"https://github.com/dotnet/announcements/issues/397","confidence_score":0.82,"first_seen":"2026-05-18","source_count":1} {"type":"domain","value":"asp.net","confidence_score":0.75,"first_seen":"2026-05-18","source_count":1}

📚 Advisory References

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