Rust has been extensively used in software and system development due to its guarantees for memory and concurrency safety. Fuzzing is a popular bug detection technique for examining the correctness and robustness of programs. However, we identify that current state-of-the-art Rust fuzzers are significantly impeded by the ubiquitous presence of Rust runtime safety checks, resulting in poor effectiveness and efficiency. These checks, which are inserted either implicitly by the compiler or explicitly by the compiler or developers, could cause a high number of panic crashes and early program termination in fuzzing. Consequently, current fuzzers are unable to effectively explore deep code behind the runtime safety checks, leaving potential vulnerabilities undetected.

The vast amount of sensitive data in modern web applications has become a prime target for cyberattacks. Existing browser security policies disallow the execution of unknown scripts, but do not restrict access to sensitive web content by 'trusted' third-party scripts. Therefore, the over-privileged third-party scripts can compromise the confidentiality and integrity of sensitive user data in the applications.