GoKawiilSecurity researcher demonstrates method to invoke JavaScript functions without parentheses
A security researcher has revealed a technique to execute JavaScript functions without using traditional parentheses. The method involves manipulating the Error object's prepareStackTrace function and overriding array prototype methods to generate and invoke arbitrary code. This approach leverages prototype pollution and custom toString or valueOf functions to trigger execution.
GoKawiil's interpretation of the reporting above, not reported fact.
This discovery highlights potential vulnerabilities in JavaScript environments where error handling and prototype manipulation are not properly secured. It suggests that malicious actors could exploit such techniques to execute arbitrary code in affected applications, emphasizing the importance of strict input validation and secure coding practices.
- Technique exploits Error.prepareStackTrace to generate functions
- Prototype pollution is key to manipulating code execution
- Overriding toString or valueOf enables function invocation without parentheses
Source: blog.ikaes.de, 2026-10-13
Published there as: “Yet another way to invoke functions without parentheses”
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