Cross-session PubSub topic injection via URL parameter in phoenix_storybook

Weakness Type (CWE)

CWE-639 — CWE-639 Authorization Bypass Through User-Controlled Key

CAPEC

CAPEC-12 — CAPEC-12 Choosing Message Identifier

CVSS 4.0 Score

2.3

LOW

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Vulnerability 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

`pkg:hex/phoenix_storybook`

Module	Source File	Routine
`PhoenixStorybook.Story.ComponentIframeLive`	`lib/phoenix_storybook/live/story/component_iframe_live.ex`	`PhoenixStorybook.Story.ComponentIframeLive.handle_params/3`

Status	Type	Version	Changes / Fixed in
affected	semver ^ⓘ	`0.4.0`	< `1.1.0`

`pkg:github/phenixdigital/phoenix_storybook`

Module	Source File	Routine
`PhoenixStorybook.Story.ComponentIframeLive`	`lib/phoenix_storybook/live/story/component_iframe_live.ex`	`PhoenixStorybook.Story.ComponentIframeLive.handle_params/3`

Status	Type	Version	Changes / Fixed in
affected	git ^ⓘ	`8c2c97b0f5`	< `6ee03f1c73`

References

https://github.com/phenixdigital/phoenix_storybook/security/advisories/GHSA-mrhx-6pw9-q5fh vendor-advisory related
https://osv.dev/vulnerability/EEF-CVE-2026-47068 related
https://github.com/phenixdigital/phoenix_storybook/commit/6ee03f1c738d4436dde1b066cf65c80663d489f5 patch

Credits

Finder: Peter Ullrich
Remediation developer: Christian Blavier
Analyst: Jonatan Männchen

CVE record as JSON: GET /cves/CVE-2026-47068.json
OSV record as JSON: GET /osv/EEF-CVE-2026-47068.json