Out-of-bounds heap writes via unchecked capacity

Integer overflow in Google Abseil C++ allows attackers to cause out-of-bounds heap writes by requesting an oversized hash container. The sized constructors, reserve(), and rehash() paths for flat and node hash containers accepted unbounded sizes, allowing backing-store arithmetic to wrap before allocation and subsequent writes. Exploitation requires a consuming application to pass an attacker-controlled, extremely large container size; downstream behavior includes invalid memory access or a process crash.