Müller was 46 and worked as a senior software engineer for SUSE Linux in Nuremberg.
In a tribute, the Samba project said: "Lars was known for his red hair, crooked smile, stubbornness, but above all, his willingness to go to any length to welcome a visitor or help anyone in need.
"His positive outlook despite overwhelming circumstances taught all of us what is most important in life."
"But first of all Lars was a brave, honest and modest person, never afraid of sharing his valuable opinions that always came with great self-irony and reflection. He will be missed and never forgotten."
There is no indication of the cause of death.
A SUSE spokesperson said the details could not be provided due to Germany's data protection laws.
Samba is a project begun by Australian developer Andrew Tridgell and provides an important component to integrate Linux/Unix Servers and Desktops into Active Directory environments.
It can function both as a domain controller or as a regular domain member.