CVE-2026-54498 in ViewComponent
Summary
by MITRE • 07/17/2026
view_component is a framework for building reusable, testable, and encapsulated view components in Ruby on Rails. From 4.0.0 until 4.12.0, ViewComponent::Base#around_render can return HTML-unsafe strings that bypass the escaping behavior applied to normal #call return values. This creates an XSS risk when downstream applications use around_render to wrap, replace, instrument, or conditionally return content that includes user-controlled data, and ViewComponent::Collection#render_in can amplify the issue by joining per-item results and marking the entire output html_safe, converting raw unsafe output into an ActiveSupport::SafeBuffer. This issue is fixed in version 4.12.0.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/17/2026
The vulnerability in ViewComponent affects Ruby on Rails applications that utilize the view_component framework for building reusable view components. This security flaw exists specifically in versions 4.0.0 through 4.12.0 and stems from improper handling of HTML escaping within the rendering pipeline. The core issue manifests in two primary methods: ViewComponent::Base#around_render and ViewComponent::Collection#render_in, both of which can produce HTML-unsafe strings that bypass normal escaping mechanisms applied to standard component return values.
The technical flaw occurs because around_render method does not properly sanitize or escape content when it returns HTML strings that contain user-controlled data. When developers use around_render for wrapping, replacing, instrumenting, or conditionally returning content, the framework fails to maintain consistent security boundaries around user input. This creates a path for malicious actors to inject cross-site scripting payloads through components that process untrusted data. The vulnerability is particularly dangerous because it operates at the component level where user input often flows through multiple layers of processing before reaching the final output.
The operational impact becomes significantly amplified when ViewComponent::Collection#render_in is involved, as this method aggregates individual component outputs and explicitly marks the combined result as html_safe. This action converts potentially unsafe raw output into an ActiveSupport::SafeBuffer, which then propagates through the rendering pipeline with elevated privilege levels. The collection rendering behavior essentially transforms a localized security issue into a broader vulnerability that can affect entire sections of an application's user interface. Attackers can leverage this to execute malicious scripts in the context of authenticated users' browsers, potentially leading to session hijacking, data exfiltration, or other malicious activities.
This vulnerability maps directly to CWE-79 Cross-Site Scripting and aligns with ATT&CK techniques related to command and control through web application exploitation. The flaw demonstrates poor input validation and output encoding practices that violate fundamental security principles for handling user-controlled content in web applications. Organizations using affected versions of ViewComponent should prioritize immediate patching to version 4.12.0 or later, while also reviewing their component implementations to ensure proper sanitization of user data before it enters the rendering pipeline.
Mitigation strategies beyond patching include implementing comprehensive input validation at multiple layers of the application, establishing strict content security policies for rendered outputs, and conducting regular security reviews of component-based code patterns. Organizations should also consider implementing automated scanning tools that can detect potentially unsafe usage patterns in their view component implementations. The fix in version 4.12.0 addresses both the immediate escaping bypass in around_render and the amplification effect in render_in by ensuring consistent HTML sanitization behavior across all component rendering paths, thereby restoring proper security boundaries between trusted and untrusted content processing.