Preliminary analysis on the GCC 9 & 10 memcmp bug suggests it CAN affect #Bitcoin Core & Knots, but does NOT affect the Bitcoin consensus code (phew).
If yours was compiled with GCC 9/10, use caution for now (or rebuild with GCC 8).
Affected: p2p & PSBT
Note that gitian builds use GCC 7 and LLVM, so should be unaffected.
PPAs for Ubuntu 20.04 (Focal) and 20.10 (Groovy) are affected (and will not be fixed immediately).
Bitcoin Maston Instance