CVE-2026-128069
Received
Received - Intake
Cross-Site Scripting in Rails HTML Sanitizer
Vulnerability report for CVE-2026-128069, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-13
Last updated on: 2026-11-13
Assigner: GitHub, Inc.
Description
Description
rails-html-sanitizer is responsible for sanitizing HTML fragments in Rails applications. Before 1.7.2, the HTML4 and HTML5 variants of Rails::HTML::SafeListSanitizer reuse one Rails::HTML::PermitScrubber across calls and mutate its tags and attributes without synchronization. In a multithreaded process, concurrent sanitize calls using different tags: or attributes: options can interleave and cause one call to use the other call's allowlist. If a permissive call admits a script element or event-handler attribute, output expected to be sanitized under a stricter policy can retain it and cause cross-site scripting when rendered. Applications that are single-threaded, use one identical allowlist everywhere, or provide a separate scrubber: are not affected. This issue is fixed in version 1.7.2.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| rails-html-sanitizer | rails-html-sanitizer | 1.7.2 |
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. |
| CWE-362 | The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. |
