CVE-2026-47068: Cross-session PubSub topic injection via URL parameter in phoenix_storybook

Severity: low (CVSS 2.3 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-20 · updated 2026-07-23
Weakness: CWE-639

Description

Authorization Bypass Through User-Controlled Key vulnerability in phenixdigital phoenix_storybook allows cross-session PubSub topic injection via a URL query parameter. 'Elixir.PhoenixStorybook.Story.ComponentIframeLive':handle_params/3 in lib/phoenix_storybook/live/story/component_iframe_live.ex reads a PubSub topic directly from params["topic"] and broadcasts {:component_iframe_pid, self()} on it with no check that the topic belongs to the requesting session. The shared PhoenixStorybook.PubSub is used to coordinate playground LiveViews with their iframes: a playground subscribes to a session-specific topic and uses the received iframe pid to direct subsequent control messages (variation state, theme switches, extra-assign payloads) via send/2. Because the iframe trusts the query parameter, an attacker who loads /storybook/iframe/<story>?topic=<victim_topic> causes their iframe process pid to be announced on the victim's topic. The victim's playground then addresses its private messages to the attacker's iframe process. This issue affects phoenix_storybook from 0.4.0 before 1.1.0.

Affected products

phenixdigital phoenix_storybook: from 0.4.0 before 1.1.0 — fixed in 1.1.0

How to fix

Upgrade to a fixed version: phenixdigital phoenix_storybook 1.1.0. Check the vendor advisory for mitigations.

References

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