What’s Vulnerable › Vulnerabilities
CVE-2024-28121: Reflex arbitrary method call in stimulus_reflex
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.6% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2024-03-12 · updated 2026-06-17
- Weakness: CWE-470
Description
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.
Affected products
- stimulusreflex Stimulusrelfex: before 3.4.2; 3.5.0-pre1, 3.5.0-pre10, 3.5.0-pre2, 3.5.0-pre3, 3.5.0-pre4, 3.5.0-pre5 (+7) — fixed in 3.4.2
How to fix
Upgrade to a fixed version: stimulusreflex Stimulusrelfex 3.4.2. Check the vendor advisory for mitigations.
References
- http://seclists.org/fulldisclosure/2024/Mar/16
- https://github.com/stimulusreflex/stimulus_reflex/blob/0211cad7d60fe96838587f159d657e44cee51b9b/app/channels/stimulus_reflex/channel.rb#L83
- https://github.com/stimulusreflex/stimulus_reflex/commit/538582d240439aab76066c72335ea92096cd0c7f
- https://github.com/stimulusreflex/stimulus_reflex/releases/tag/v3.4.2
- https://github.com/stimulusreflex/stimulus_reflex/releases/tag/v3.5.0.rc4
- https://github.com/stimulusreflex/stimulus_reflex/security/advisories/GHSA-f78j-4w3g-4q65
- http://seclists.org/fulldisclosure/2024/Mar/16
- https://github.com/stimulusreflex/stimulus_reflex/blob/0211cad7d60fe96838587f159d657e44cee51b9b/app/channels/stimulus_reflex/channel.rb#L83
- https://github.com/stimulusreflex/stimulus_reflex/commit/538582d240439aab76066c72335ea92096cd0c7f
- https://github.com/stimulusreflex/stimulus_reflex/releases/tag/v3.4.2
- https://github.com/stimulusreflex/stimulus_reflex/releases/tag/v3.5.0.rc4
- https://github.com/stimulusreflex/stimulus_reflex/security/advisories/GHSA-f78j-4w3g-4q65
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