Microsoft Security Advisory CVE-2026-45591 – ASP.NET Core Denial of Service Vulnerability

Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core SignalR and Blazor Server. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. A denial of service...

Symlink Attack

Overview Affected versions of this package are vulnerable to Symlink Attack via improper link resolution before file access. An attacker can modify local files by exploiting symbolic links to redirect file operations to unintended locations. Remediation Upgrade...

Infinite loop

Overview Microsoft.AspNetCore.App.Runtime.linux-musl-arm is a package providing a default set of APIs for building an ASP.NET Core application. Contains assets used for self-contained deployments. Affected versions of this package are vulnerable to Infinite loop in the...

HTTP Response Splitting

Overview Affected versions of this package are vulnerable to HTTP Response Splitting via the MailAddressParser.TryParseAddress function due to improper neutralisation of CRLF sequences. An attacker can impersonate another user or entity by sending specially crafted data over the network...

Out-of-bounds Read

Overview Affected versions of this package are vulnerable to Out-of-bounds Read when decoding malformed Base64Url input. An attacker can cause a disruption of service. Remediation Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to version 9.0.14, 10.0.4 or higher. References - GitHub Commit ...

Incorrect Default Permissions

Overview Affected versions of this package are vulnerable to Incorrect Default Permissions. An attacker can gain elevated privileges by exploiting these permissions locally. Remediation Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to version 10.0.4 or higher. References - Vulnerability...

Inadequate Encryption Strength

Overview Affected versions of this package are vulnerable to Inadequate Encryption Strength via the SMTP process. An attacker can intercept sensitive information by performing a man-in-the-middle attack that prevents the use of TLS, causing data to be sent over an unencrypted connection...

HTTP Request Smuggling

Overview Microsoft.AspNetCore.App.Runtime.linux-musl-arm is a package providing a default set of APIs for building an ASP.NET Core application. Contains assets used for self-contained deployments. Affected versions of this package are vulnerable to HTTP Request Smuggling via the interpretation of...

Buffer Over-read

Overview Affected versions of this package are vulnerable to Buffer Over-read via the DiaSymReader.dll process. An attacker can execute arbitrary code by exploiting a buffer over-read condition when the application processes specially crafted input. This issue affects EOL ASP.NET 6.0.0 = 6.0.36 a...

Integer Overflow or Wraparound

Overview Affected versions of this package are vulnerable to Integer Overflow or Wraparound due to improper handling of integer values in the msdia140.dll process. An attacker can execute arbitrary code by supplying specially crafted input that triggers an integer overflow and subsequent heap-bas...

Allocation of Resources Without Limits or Throttling

Overview Microsoft.AspNetCore.App.Runtime.linux-musl-arm is a package providing a default set of APIs for building an ASP.NET Core application. Contains assets used for self-contained deployments. Affected versions of this package are vulnerable to Allocation of Resources Without Limits or...

Improper Authentication

Overview Microsoft.AspNetCore.App.Runtime.linux-musl-arm is a package providing a default set of APIs for building an ASP.NET Core application. Contains assets used for self-contained deployments. Affected versions of this package are vulnerable to Improper Authentication in the RefreshSignInAsyn...

Buffer Over-read

Overview Affected versions of this package are vulnerable to Buffer Over-read through the loading of a specially crafted file. Remediation Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to version 8.0.12, 9.0.1 or higher. References - GitHub Issue - GitHub Issue - Security Advisory...

Heap-based Buffer Overflow

Overview Affected versions of this package are vulnerable to Heap-based Buffer Overflow through the loading of a specially crafted file. Remediation Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to version 8.0.12, 9.0.1 or higher. References - GitHub Issue...

Heap-based Buffer Overflow

Overview Affected versions of this package are vulnerable to Heap-based Buffer Overflow. An attacker can execute arbitrary code by sending malicious requests designed to exploit the vulnerability. Remediation Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to version 9.0.1 or higher...

Use After Free

Overview Microsoft.AspNetCore.App.Runtime.linux-musl-arm is a package providing a default set of APIs for building an ASP.NET Core application. Contains assets used for self-contained deployments. Affected versions of this package are vulnerable to Use After Free that could allow remote code...

Cleartext Transmission of Sensitive Information

Overview Affected versions of this package are vulnerable to Cleartext Transmission of Sensitive Information via the TlsStream process. An attacker can gain access to sensitive information by intercepting unencrypted data. Remediation Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to versio...

Use After Free

Overview Microsoft.AspNetCore.App.Runtime.linux-musl-arm is a package providing a default set of APIs for building an ASP.NET Core application. Contains assets used for self-contained deployments. Affected versions of this package are vulnerable to Use After Free through the handling of HTTP/3...

Race Condition

Overview Microsoft.AspNetCore.App.Runtime.linux-musl-arm is a package providing a default set of APIs for building an ASP.NET Core application. Contains assets used for self-contained deployments. Affected versions of this package are vulnerable to Race Condition through the...

Heap-based Buffer Overflow

Overview Affected versions of this package are vulnerable to Heap-based Buffer Overflow due to a stack buffer overrun in the Double Parse routine. An attacker can execute arbitrary code by supplying a specially crafted input that triggers the buffer overrun. Remediation Upgrade...