CWE-917

Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

High

Description

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.

Potential Impact

How to Fix

Architecture and Design

Avoid adding user-controlled data into an expression interpreter when possible.

Implementation

If user-controlled data must be added to an expression interpreter, one or more of the following should be performed: Validate that the user input will not evaluate as an expression Encode the user input in a way that ensures it is not evaluated as an expression

System Configuration

The framework or tooling might allow the developer to disable or deactivate the processing of EL expressions, such as setting the isELIgnored attribute for a JSP page to "true".

Detection Methods

Related Weaknesses

References

View on MITRE CWE Database →

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