Title: phoenix_storybook de phenixdigital, Description: Vulnerabilidad de inyección de código en phenixdigital phoenix_storybook permite la ejecución remota de código no autenticada a través de la interpolación de valores de atributos no saneados en la generación de plantillas HEEx.

El gestor de eventos WebSocket psb-assign en 'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive':handle_event/3 acepta nombres y valores de atributos arbitrarios de clientes no autenticados. Estos valores se pasan a 'Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers':handle_set_variation_assign/3, que los almacena textualmente. Al renderizar, 'Elixir.PhoenixStorybook.Rendering.ComponentRenderer':attributes_markup/1 interpola valores de atributos binarios directamente en una cadena de plantilla HEEx como name="<val>" sin escapar las comillas dobles o los delimitadores de expresión HEEx. Un atacante puede proporcionar un valor que contenga una comilla de cierre seguida de un bloque de expresión HEEx (p. ej., foo" injected={EXPR} bar="), lo que hace que EXPR sea tratado como una expresión Elixir en línea. La plantilla resultante se compila a través de EEx.compile_string/2 y se ejecuta a través de Code.eval_quoted_with_env/3 con importaciones completas del Kernel y sin sandbox, lo que le da al atacante ejecución de código arbitrario en el servidor.

Este problema afecta a phoenix_storybook desde 0.5.0 antes de 1.1.0.

{"timestamp":"2026-05-21T13:57:52.803277Z","id":"CVE-2026-8467","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}

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https://github.com/phenixdigital/phoenix_storybook/security/advisories/GHSA-55hg-8qxv-qj4p

Code Injection vulnerability in phenixdigital phoenix_storybook allows unauthenticated remote code execution via unsanitized attribute value interpolation in HEEx template generation.

The psb-assign WebSocket event handler in 'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive':handle_event/3 accepts arbitrary attribute names and values from unauthenticated clients. These values are passed to 'Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers':handle_set_variation_assign/3, which stores them verbatim. When rendering, 'Elixir.PhoenixStorybook.Rendering.ComponentRenderer':attributes_markup/1 interpolates binary attribute values directly into a HEEx template string as name="<val>" without escaping double quotes or HEEx expression delimiters. An attacker can supply a value containing a closing quote followed by a HEEx expression block (e.g. foo" injected={EXPR} bar="), which causes EXPR to be treated as an inline Elixir expression. The resulting template is compiled via EEx.compile_string/2 and executed via Code.eval_quoted_with_env/3 with full Kernel imports and no sandbox, giving the attacker arbitrary code execution on the server.

This issue affects phoenix_storybook from 0.5.0 before 1.1.0.

AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CWE-94

https://cna.erlef.org/cves/CVE-2026-8467.html

https://github.com/phenixdigital/phoenix_storybook/commit/56ab8464d4375fa52db806148a06cce126ad481d

https://github.com/phenixdigital/phoenix_storybook/security/advisories/GHSA-55hg-8qxv-qj4p

https://osv.dev/vulnerability/EEF-CVE-2026-8467