Improper Handling of Inconsistent Special Elements

The product does not properly handle input in which an inconsistency exists between two or more special characters or reserved words.

An example of this problem would be if paired characters appear in the wrong order, or if the special characters are not properly nested.

We track 2 vulnerabilities of this type. 100% are rated high or critical, and the average CVSS score is 7.5.

How this weakness is prevented

• Developers should anticipate that inconsistent special elements will be injected/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
• Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.