Backslash Vulnerability Database 
Variable Extraction Error
Variable Extraction Error
Variable Extraction Error
CWE-621
Per technology (GHSA, All time)
- 100%-Composer
Short description
The product uses external input to determine the names of variables into which information is extracted, without verifying that the names of the specified variables are valid. This could cause the program to overwrite unintended variables.
Extended description
For example, in PHP, extraction can be used to provide functionality similar to register_globals, a dangerous functionality that is frequently disabled in production systems. Calling extract() or import_request_variables() without the proper arguments could allow arbitrary global variables to be overwritten, including superglobals.
Similar functionality is possible in other interpreted languages, including custom languages.
Best practices to prevent this CWE
Phase: Implementation
Strategy: Input Validation
Use allowlists of variable names that can be extracted.
Phase: Implementation
Consider refactoring your code to avoid extraction routines altogether.
Phase: Implementation
In PHP, call extract() with options such as EXTR_SKIP and EXTR_PREFIX_ALL; call import_request_variables() with a prefix argument. Note that these capabilities are not present in all PHP versions.
