Vulnerability RUSTSEC-2024-0444
Summary
Uncaught exception when transitioning the state of `AsyncGenerator` objects from within a property getter of `then`
Details
A wrong assumption made when handling ECMAScript's AsyncGenerator operations can cause an uncaught exception on certain scripts.
Details
Boa's implementation of AsyncGenerator makes the assumption that the state of an AsyncGenerator object cannot change while resolving a promise created by methods of AsyncGenerator such as %AsyncGeneratorPrototype%.next, %AsyncGeneratorPrototype%.return, or %AsyncGeneratorPrototype%.throw.
However, a carefully constructed code could trigger a state transition from a getter method for the promise's then property, which causes the engine to fail an assertion of this assumption, causing an uncaught exception. This could be used to create a Denial Of Service attack in applications that run arbitrary ECMAScript code provided by an external user.
Patches
Version 0.19.0 is patched to correctly handle this case.
Workarounds
Users unable to upgrade to the patched version would want to use std::panic::catch_unwind to ensure any exceptions caused by the engine don't impact the availability of the main application.
Related Vulnerabilities
Other vulnerabilities affecting the same packages
