CWE 787

Out-of-bounds Write

Weakness ID: 787 (Weakness Base)

Status: Incomplete

Description

Description Summary

The software writes data past the end, or before the beginning, of the intended buffer.

Extended Description

This typically occurs when the pointer or its index is incremented or decremented to a position beyond the bounds of the buffer or when pointer arithmetic results in a position outside of the valid memory location to name a few. This may result in corruption of sensitive information, a crash, or code execution among other things.

Demonstrative Examples

Example 1

The following code attempts to save four different identification numbers into an array.

(Bad Code)

Example Language: C

int id_sequence[3];

/* Populate the id array. */

id_sequence[0] = 123;

id_sequence[1] = 234;

id_sequence[2] = 345;

id_sequence[3] = 456;

Relationships

Nature	Type	ID	Name	View(s) this relationship pertains to
ChildOf	Weakness Class	119	Failure to Constrain Operations within the Bounds of a Memory Buffer	Development Concepts (primary)699 Research Concepts (primary)1000
ParentOf	Weakness Variant	121	Stack-based Buffer Overflow	Development Concepts699 Research Concepts1000
ParentOf	Weakness Variant	122	Heap-based Buffer Overflow	Development Concepts699 Research Concepts1000
ParentOf	Weakness Base	124	Buffer Underwrite ('Buffer Underflow')	Development Concepts699 Research Concepts1000