CVE-2026-26171: .NET Denial of Service Vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-14 · updated 2026-10-26
Weakness: CWE-400

Description

Uncontrolled resource consumption in .NET allows an unauthorized attacker to deny service over a network.

Affected products

Microsoft .NET: from 10.0.0 before 10.0.6; from 8.0.0 before 8.0.26; from 9.0.0 before 9.0.15 — fixed in 10.0.6, 8.0.26, 9.0.15
Microsoft Powershell: from 7.5 before 7.5.6; from 7.6 before 7.6.1 — fixed in 7.5.6, 7.6.1
Microsoft .NET: from 10.0.0 before 10.0.6 — fixed in 10.0.6
Microsoft .NET 8.0: from 8.0.0 before 8.0.26 — fixed in 8.0.26
Microsoft .NET 9.0: from 9.0.0 before 9.0.15 — fixed in 9.0.15
Microsoft PowerShell 7.5: from 7.5.0 before 7.5.6 — fixed in 7.5.6
Microsoft PowerShell 7.6: from 7.6.0 before 7.6.1 — fixed in 7.6.1

How to fix

Upgrade to a fixed version: Microsoft .NET 10.0.6, 8.0.26, 9.0.15; Microsoft Powershell 7.5.6, 7.6.1; Microsoft .NET 10.0.6; Microsoft .NET 8.0 8.0.26; Microsoft .NET 9.0 9.0.15; Microsoft PowerShell 7.5 7.5.6; Microsoft PowerShell 7.6 7.6.1. Check the vendor advisory for mitigations.

References

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