CVE-2026-33168

Received Received - Intake

XSS Vulnerability in Rails Action View via Malformed HTML Attributes

Publication date: 2026-03-23

Last updated on: 2026-03-23

Assigner: GitHub, Inc.

Description

Action View provides conventions and helpers for building web pages with the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, when a blank string is used as an HTML attribute name in Action View tag helpers, the attribute escaping is bypassed, producing malformed HTML. A carefully crafted attribute value could then be misinterpreted by the browser as a separate attribute name, possibly leading to XSS. Applications that allow users to specify custom HTML attributes are affected. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-03-23

Last Modified

2026-03-23

Generated

2026-07-06

AI Q&A

2026-03-24

EPSS Evaluated

2026-07-05

NVD

CVE-2026-33168

Affected Vendors & Products

Vendor	Product	Version / Range
rubyonrails	action_view	to 7.2.3.1 (exc)

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.

Attack-Flow Graph

Executive Summary

This vulnerability exists in the Action View component of the Rails framework, which helps build web pages. Before certain patched versions, if a blank string was used as an HTML attribute name in Action View tag helpers, the escaping of that attribute was bypassed. This caused malformed HTML to be generated.

Because of this malformed HTML, a carefully crafted attribute value could be interpreted by the browser as a separate attribute name, which could lead to cross-site scripting (XSS) attacks.

Applications that allow users to specify custom HTML attributes are particularly affected by this issue.

Impact Analysis

This vulnerability can lead to cross-site scripting (XSS) attacks, where an attacker injects malicious scripts into web pages viewed by other users.

Such XSS attacks can compromise user data, hijack user sessions, deface websites, or redirect users to malicious sites.

If your application allows users to specify custom HTML attributes and uses vulnerable versions of Action View, it may be exposed to these risks.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

To mitigate this vulnerability, you should upgrade the Action View component of the Rails framework to one of the patched versions: 8.1.2.1, 8.0.4.1, or 7.2.3.1.

Additionally, review your application code to ensure it does not allow users to specify custom HTML attributes that could exploit this issue.

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