The NtfsHandler.cpp NTFS handler in 7-Zip before 24.01 (for 7zz) contains a heap-based buffer overflow that allows an attacker to overwrite two bytes at multiple offsets beyond the allocated buffer size: buffer+512*i-2, for i=9, i=10, i=11, etc.
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().