Using Docker, how to change bash version inside Dockefile? - bash

Question

When I login into a running container, and issue a bash --version command I am seeing the following
root#sb-core-repo-7988897977-rdtkb:/myapp# bash --version
GNU bash, version 5.0.3(1)-release (x86_64-pc-linux-gnu)
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Since, this GNU bash version 5.0.3 has a vulnerability, I would like to update the bash to 5.1.2 apparently, the vulnerability has been fixed in that release. as per vulnerability
How and what can I update in the Dockerfile to update the bash version?
My Dockerfile is like this:
FROM mcr.microsoft.com/dotnet/core/aspnet:3.1 AS base
WORKDIR /myapp
EXPOSE 80
## Installing tools for dotnet core
FROM mcr.microsoft.com/dotnet/core/sdk:3.1 As pre-build
RUN apt-get update && apt-get install -y openjdk-11-jre
ENV PATH="$PATH:/root/.dotnet/tools"
FROM pre-build AS build
WORKDIR /src
COPY ["PhantomService.Application/PhantomService.Application.csproj", "PhantomService.Application/"]
COPY ["PhantomService.RestApi/NuGet.Config", "PhantomService.RestApi/"]
RUN dotnet restore "PhantomService.RestApi/PhantomService.RestApi.csproj" --configfile "PhantomService.RestApi/NuGet.Config"
## Build and Test
RUN dotnet build "PhantomService.RestApi/PhantomService.RestApi.csproj" -c Release -o /myapp
FROM build AS publish
RUN dotnet publish "PhantomService.RestApi/PhantomService.RestApi.csproj" -c Release -o /myapp
FROM base AS final
WORKDIR /myapp
COPY --from=publish /myapp .
ENTRYPOINT ["dotnet", "PhantomService.RestApi.dll"]
appreciate all the help and advice