CWE-194: Unexpected 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.
- Abstraction
- VariantA weakness tied to a specific language, technology or resource.
- Likelihood of exploit
- High
- Status
- Incomplete
Common consequences
- IntegrityConfidentialityAvailabilityOther
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 numeric value is associated with an application-level resource, such as a quantity or...
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 weaknesses
Parent weaknesses
CAPEC attack patterns that exploit it
CWE 4.20 links no CAPEC attack pattern to this weakness.