CVE-2024-28121: Stimulusreflex Stimulusrelfex vulnerability (CVSS 8.8)

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredLow

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Stimulusreflex Stimulusrelfex< 3.4.2 · 3.5.0

Remediation

Fixed in

Stimulusreflex Stimulusrelfex≥ 3.4.2

Patch & vendor advisories

References

http://seclists.org/fulldisclosure/2024/Mar/16ExploitThird Party Advisory
https://github.com/stimulusreflex/stimulus_reflex/blob/0211cad7d60fe96838587f159d657e44cee51b9b/app/channels/stimulus_reflex/channel.rb#L83Technical Description
https://github.com/stimulusreflex/stimulus_reflex/commit/538582d240439aab76066c72335ea92096cd0c7fPatch
https://github.com/stimulusreflex/stimulus_reflex/releases/tag/v3.4.2ProductRelease Notes
https://github.com/stimulusreflex/stimulus_reflex/releases/tag/v3.5.0.rc4ProductRelease Notes
https://github.com/stimulusreflex/stimulus_reflex/security/advisories/GHSA-f78j-4w3g-4q65ExploitVendor Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2024-28121 being actively exploited?

CVE-2024-28121 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.55%.

How severe is CVE-2024-28121?

CVE-2024-28121 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 1.55% probability of exploitation.

Which products are affected by CVE-2024-28121?

Affected products include Stimulusreflex Stimulusrelfex.

How do I fix CVE-2024-28121?

Upgrade affected software to a fixed version, for example Stimulusreflex Stimulusrelfex 3.4.2 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2024-28121 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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