Improper Restriction of Operations within the Bounds of a Memory Buffer
folly::secureRandom will re-use a buffer between parent and child processes when fork() is called. That will result in multiple forked children producing repeat (or similar) results. This affects HHVM 3.26 prior to 3.26.3 and the folly library between v2017.12.11.00 and v2018.08.09.00.
CWE-119 - Buffer Overflow
Buffer overflow attacks involve data transit and operations exceeding the restricted memory buffer, thereby corrupting or overwriting data in adjacent memory locations. Such overflow allows the attacker to run arbitrary code or manipulate the existing code to cause privilege escalation, data breach, denial of service, system crash and even complete system compromise. Given that languages such as C and C++ lack default safeguards against overwriting or accessing data in their memory, applications utilizing these languages are most susceptible to buffer overflows attacks.