decNumberCopy in decNumber.c in jq through 1.7.1 does not properly consider that NaN is interpreted as numeric, which has a resultant stack-based buffer overflow and out-of-bounds write, as demonstrated by use of --slurp with subtraction, such as a filter of .-. when the input has a certain form of digit string with NaN (e.g., "1 NaN123" immediately followed by many more digits).
The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.