CVE-2026-70159: ASP.NET Core Denial of Service Vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-13 · updated 2026-10-31
Weakness: CWE-770

Description

Allocation of resources without limits or throttling in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Affected products

Microsoft.AspNetCore.SignalR.Common: from 10.0.0 before 10.0.13 — fixed in 10.0.13
Microsoft.AspNetCore.SignalR.Core: from 1.0.0 before 1.2.14 — fixed in 1.2.14
Microsoft Visual Studio 2026 version 18.10: from 18.10.0 before 18.10.4 — fixed in 18.10.4
Microsoft Visual Studio 2022 version 17.14: from 17.14.0 before 17.14.42 — fixed in 17.14.42

How to fix

Upgrade to a fixed version: Microsoft.AspNetCore.SignalR.Common 10.0.13; Microsoft.AspNetCore.SignalR.Core 1.2.14; Microsoft Visual Studio 2026 version 18.10 18.10.4; Microsoft Visual Studio 2022 version 17.14 17.14.42. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70159

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