CWE-185

Incorrect Regular Expression
AI Translation Available

The product specifies a regular expression in a way that causes data to be improperly matched or compared.

Status
draft
Abstraction
class

When the regular expression is used in protection mechanisms such as filtering or validation, this may allow an attacker to bypass the intended restrictions on the incoming data.

Common Consequences

other access control
Impacts
unexpected state varies by context bypass protection mechanism

Detection Methods

automated static analysis

Potential Mitigations

Phases:
architecture and design
Descriptions:
• Regular expressions can become error prone when defining a complex language even for those experienced in writing grammars. Determine if several smaller regular expressions simplify one large regular expression. Also, subject the regular expression to thorough testing techniques such as equivalence partitioning, boundary value analysis, and robustness. After testing and a reasonable confidence level is achieved, a regular expression may not be foolproof. If an exploit is allowed to slip through, then record the exploit and refactor the regular expression.