Reflex arbitrary method call in stimulus_reflex

Summary

stimulus_reflex is a system to extend the capabilities of both Rails and Stimulus by intercepting user interactions and passing them to Rails over real-time websockets. In affected versions more methods than expected can be called on reflex instances. Being able to call some of them has security implications. To invoke a reflex a websocket message of the following shape is sent: `\"target\":\"[class_name]#[method_name]\",\"args\":[]`. The server will proceed to instantiate `reflex` using the provided `class_name` as long as it extends `StimulusReflex::Reflex`. It then attempts to call `method_name` on the instance with the provided arguments. This is problematic as `reflex.method method_name` can be more methods that those explicitly specified by the developer in their reflex class. A good example is the instance_variable_set method. This vulnerability has been patched in versions 3.4.2 and 3.5.0.rc4. Users unable to upgrade should: see the backing GHSA advisory for mitigation advice.

Timeline

1. Mar 12, 2024, 7:44 PM UTCCVE published
2. Mar 13, 2024, 2:29 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Feb 13, 2025, 5:47 PM UTCRecord last updated

Affected versions

• stimulusreflex stimulus_reflex

  From 3.5.0.rc1 · fixed in 3.5.0.rc4; fixed in 3.4.2

• stimulus_reflexRubyGems

  From 3.5.0.pre0 · fixed in 3.5.0.rc4

• stimulus_reflexRubyGems

  fixed in 3.4.2

• stimulus_reflexnpm

  From 3.5.0-pre0 · fixed in 3.5.0-rc4

• stimulus_reflexnpm

  fixed in 3.4.2

References 6