Arch Linux: ASA-202103-20 Severe Dotnet Runtime Code Execution Flaw

Arch Linux Security Advisory ASA-202103-20
=========================================
Severity: High
Date    : 2021-03-25
CVE-ID  : CVE-2021-26701
Package : dotnet-runtime
Type    : arbitrary code execution
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1698

Summary
======
The package dotnet-runtime before version 5.0.4.sdk104-1 is vulnerable
to arbitrary code execution.

Resolution
=========
Upgrade to 5.0.4.sdk104-1.

# pacman -Syu "dotnet-runtime>=5.0.4.sdk104-1"

The problem has been fixed upstream in version 5.0.4.sdk104.

Workaround
=========
None.

Description
==========
A remote code execution vulnerability exists in .NET 5.0 before Runtime
5.0.4 and SDK 5.0.104 as well as .NET Core 3.1 before Runtime 3.1.13
and SDK 3.1.113 due to how text encoding is performed in the
System.Text.Encodings.Web package, caused by a buffer overrun.

Impact
=====
An attacker can execute arbitrary code by abusing the text encoding.

References
=========
https://bugs.archlinux.org/task/69317

https://github.com/dotnet/announcements/issues/178
https://security.archlinux.org/CVE-2021-26701