In SQLite 3.44.0 through 3.49.0 before 3.49.1, the concatws() SQL function can cause memory to be written beyond the end of a malloc-allocated buffer. If the separator argument is attacker-controlled and has a large string (e.g., 2MB or more), an integer overflow occurs in calculating the size of the result buffer, and thus malloc may not allocate enough memory.

An integer overflow can be triggered in SQLite’s concatws() function. The resulting, truncated integer is then used to allocate a buffer. When SQLite then writes the resulting string to the buffer, it uses the original, untruncated size and thus a wild Heap Buffer overflow of size ~4GB can be triggered. This can result in arbitrary code execution.