An out-of-bounds write exists in the PEA archive extraction routine within the `unpea procedure` function of the `pea.pas` file. The issue occurs when decompressing a PCOMPRESS1 stream, where the 32-bit compressed-block-size field of the first block (`compsize`) is read from the archive and used without validation as the length for a block read into the fixed-size global buffers `wbuf1` and `wbuf2` (1,114,112 bytes). This allows the first block to bypass the `compsize > WBUFSIZE` check, leading to an out-of-bounds read at an attacker-chosen offset via `wbuf1[compsize]`. Additionally, the copy loop uses the requested length instead of the actual bytes read and terminates on equality rather than an upper bound. This memory corruption can be triggered by opening or extracting a crafted .pea archive, potentially allowing arbitrary code execution as the user running the application across Windows, macOS, Linux, and BSD platforms.