CVE-2026-126079
Received
Received - Intake
XSS via HTML Sanitization in Action View
Vulnerability report for CVE-2026-126079, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-10
Last updated on: 2026-11-10
Assigner: GitHub, Inc.
Description
Description
Action View is a framework for handling view template lookup and rendering and provides view helpers for building HTML. Prior to 8.1.4.1 and 8.0.5.2, with the HTML5 sanitizer (Rails::HTML5::Sanitizer, the default vendor on CRuby for applications using load_defaults 7.1 or later), Nokogiri before 1.19.5 serializes < and > unescaped inside attribute values. The Action View text helpers highlight and simple_format sanitize their input and then process the resulting HTML as a string: highlight splits it on tag boundaries to insert matches, and simple_format splits it into paragraphs on blank lines. An unescaped > or a blank line inside an attribute value could cause markup in that value, which the sanitizer left inert, to be emitted as live elements in the helper's html_safe output, possibly leading to XSS. Applications that use the HTML5 sanitizer and pass untrusted text to highlight, or to simple_format with html_options, are affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| rubyonrails | action_view | 8.1.4.1 |
| rubyonrails | action_view | 8.0.5.2 |
| nokogiri | nokogiri | 1.19.5 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-79 | The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. |
