CVE-2024-45306

A heap-buffer overflow was found in Vim. Patch v9.1.0038 optimized how the cursor position is calculated and removed a loop, that verified that the cursor position always points inside a line and does not become invalid by pointing beyond the end of a line. It was assumed that this loop was unnecessary. However, this change made it possible for the cursor position to stay invalid and point beyond the end of a line, which would eventually cause a heap-buffer-overflow when trying to access the line pointer at the specified cursor position.