The various bson_append functions in the MongoDB C driver library may be susceptible to buffer overflow when performing operations that could result in a final BSON document which exceeds the maximum allowable size (INT32_MAX), resulting in a segmentation fault and possible application crash. This issue affected libbson versions prior to 1.27.5, MongoDB Server v8.0 versions prior to 8.0.1 and MongoDB Server v7.0 versions prior to 7.0.16
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().