CVE-2026-8467
Unauthenticated remote code execution via HEEx template injection in phoenix_storybook playground
Description
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.
INFO
Published Date :
May 20, 2026, 2:17 p.m.
Last Modified :
July 23, 2026, 12:10 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | CRITICAL | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | CRITICAL | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update phoenix_storybook to version 1.1.0 or later.
- Apply vendor patches if available.
- Sanitize all user-supplied attribute values.
- Validate attribute names and values strictly.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-8467.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-8467 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-8467
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-8467 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-8467 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Translated by [email protected]
Jul. 23, 2026
Action Type Old Value New Value Added Translation 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. -
CVE Modified by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:phenixdigital:phoenix_storybook:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/phenixdigital/phoenix_storybook', 'vendor': 'phenixdigital', 'modules': ['Elixir.PhoenixStorybook.Rendering.ComponentRenderer', 'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive', 'Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers'], 'product': 'phoenix_storybook', 'versions': [{'status': 'affected', 'version': '0.5.0', 'lessThan': '1.1.0', 'versionType': 'semver'}], 'packageURL': 'pkg:hex/phoenix_storybook', 'packageName': 'phoenix_storybook', 'programFiles': ['lib/phoenix_storybook/rendering/component_renderer.ex', 'lib/phoenix_storybook/live/story/playground_preview_live.ex', 'lib/phoenix_storybook/helpers/extra_assigns_helpers.ex'], 'collectionURL': 'https://repo.hex.pm', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.PhoenixStorybook.Rendering.ComponentRenderer':attributes_markup/1"}, {'name': "'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive':handle_event/3"}, {'name': "'Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers':handle_set_variation_assign/3"}]}, {'cpes': ['cpe:2.3:a:phenixdigital:phoenix_storybook:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/phenixdigital/phoenix_storybook', 'vendor': 'phenixdigital', 'modules': ['Elixir.PhoenixStorybook.Rendering.ComponentRenderer', 'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive', 'Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers'], 'product': 'phoenix_storybook', 'versions': [{'status': 'affected', 'version': 'e35379dfe2ef1a71b141899e36f431017c55265d', 'lessThan': '56ab8464d4375fa52db806148a06cce126ad481d', 'versionType': 'git'}], 'packageURL': 'pkg:github/phenixdigital/phoenix_storybook', 'packageName': 'phenixdigital/phoenix_storybook', 'programFiles': ['lib/phoenix_storybook/rendering/component_renderer.ex', 'lib/phoenix_storybook/live/story/playground_preview_live.ex', 'lib/phoenix_storybook/helpers/extra_assigns_helpers.ex'], 'collectionURL': 'https://github.com', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.PhoenixStorybook.Rendering.ComponentRenderer':attributes_markup/1"}, {'name': "'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive':handle_event/3"}, {'name': "'Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers':handle_set_variation_assign/3"}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-8467', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-05-21T13:57:52.803277Z'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 21, 2026
Action Type Old Value New Value Added Reference https://github.com/phenixdigital/phoenix_storybook/security/advisories/GHSA-55hg-8qxv-qj4p -
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
May. 20, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V4.0 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 Added CWE CWE-94 Added Reference https://cna.erlef.org/cves/CVE-2026-8467.html Added Reference https://github.com/phenixdigital/phoenix_storybook/commit/56ab8464d4375fa52db806148a06cce126ad481d Added Reference https://github.com/phenixdigital/phoenix_storybook/security/advisories/GHSA-55hg-8qxv-qj4p Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-8467