While OpenWRT is probably the standard right now there are lots of concerns
with that project. They've been hostile to free software related suggestions
in the past. A brief description of it technically speaking is: It's a mess.
I won't go into any detail, but the lead developer of LibreCMC has wanted to
(for years) clean it up. That said this doesn't mean there is some other
better project to build off. I can certainly name worse embedded
distributions from a technical and freedom perspective. That said both
LibreCMC (and LibreWRT) are derived from OpenWRT.
The lead developer of LibreCMC stripped out a lot of "garbage" from OpenWRT.
LibreCMC is being actively worked on, there are security issues being fixed,
and when an update is released I'd suggest upgrading.
The specific security issue is probably not a major issue for most people and
it's an issue that probably won't be fixed in most routers. The reason it is
not a major issue right now is there is a decent default configuration. The
issue basically impacts near all distributions and its not the bash bug
recently revealed. For those who are wondering LibreCMC does not include
bash. We've been asked that question one too many times...