A heap-based out-of-bounds read in the BufferSerializerIOv2_ReadBuffer function (src/serializers/serializer_io.c) in FalkorDB before 4.18.4 allows a remote attacker who can issue Redis replication commands (for example, against an instance with no password configured) to cause a denial of service or disclose heap memory by supplying a crafted RDB stream whose sub-buffer length field exceeds the remaining buffer size. The only bounds check is an ASSERT(), which is compiled out in release builds, so memcpy() reads past the end of the heap allocation.
Require authentication on the Redis/FalkorDB instance (requirepass or ACLs), restrict or rename the REPLICAOF/SLAVEOF commands so untrusted clients cannot use them, and do not expose the instance to untrusted networks.
Upgrade FalkorDB to version 4.18.4 or later.