CVE-2026-8467

Severity CVSS v4.0:

CRITICAL

Type:

CWE-94 Code Injection

Publication date:

20/05/2026

Last modified:

21/05/2026

Description

Code Injection vulnerability in phenixdigital phoenix_storybook allows unauthenticated remote code execution via unsanitized attribute value interpolation in HEEx template generation.<br /> <br /> The psb-assign WebSocket event handler in &#39;Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive&#39;:handle_event/3 accepts arbitrary attribute names and values from unauthenticated clients. These values are passed to &#39;Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers&#39;:handle_set_variation_assign/3, which stores them verbatim. When rendering, &#39;Elixir.PhoenixStorybook.Rendering.ComponentRenderer&#39;:attributes_markup/1 interpolates binary attribute values directly into a HEEx template string as name="" 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.<br /> <br /> This issue affects phoenix_storybook from 0.5.0 before 1.1.0.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H CVSS v4.0 Severity and Metrics:

Base Score: 9.50 CRITICAL
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): High
Confidentiality (SC): High
Integrity (SI): High
Availability (SA): High

Base Score 4.0

9.50

Severity 4.0

CRITICAL

CVE-2026-8467

Description

Impact

References to Advisories, Solutions, and Tools