CWE-194Unexpected Sign Extension

Description

The product performs an operation on a number that causes it to be sign extended when it is transformed into a larger data type. When the original number is negative, this can produce unexpected values that lead to resultant weaknesses.

Common consequences

• Integrity,Confidentiality,Availability,Other→Read Memory,Modify Memory,Other
  When an unexpected sign extension occurs in code that operates directly on memory buffers, such as a size value or a memory index, then it could cause the program to write or read outside the boundaries of the intended buffer. If the numeri

Potential mitigations

• Implementation
  Avoid using signed variables if you don't need to represent negative values. When negative values are needed, perform validation after you save those values to larger data types, or before passing them to functions that are expecting unsigned values.

Related CWEs