UBUNTU-CVE-2026-126069: XSS
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, the fix for CVE-2026-33168 skips blank HTML attribute names in Action View tag helpers, but it tests the name before converting it to a string. A Symbol name made only of whitespace, such as :" ", is not blank, because Symbol#blank? is Symbol#empty?, so it reaches the attribute escaping, which emits an attribute with no name and produces malformed HTML. The asset tag helpers, such as imagetag, videotag and audiotag, symbolize their options, so a whitespace String name passed to them takes the same path. 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 attribute names are affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Action Viewto a version that resolves this vulnerability.Fixed in 8.1.4.1 - Upgrade
Upgrade
Action Viewto a version that resolves this vulnerability.Fixed in 8.0.5.2
Event History
Frequently Asked Questions
Which applications are realistically exposed to this issue?
Applications are affected if they allow users to specify custom HTML attribute names and use Action View tag helpers. Asset helpers including image_tag, video_tag, and audio_tag are included because they symbolize their options.
What input is needed to trigger the vulnerable behavior?
An attacker needs to supply a custom attribute name consisting only of whitespace, either as a whitespace-only Symbol or, for the asset tag helpers, a whitespace String. A carefully crafted attribute value may then be interpreted by the browser as a separate attribute name, potentially enabling XSS.
Are applications using ordinary fixed attribute names affected?
The described attack condition requires user-controlled custom HTML attribute names. The provided information does not indicate exposure where attribute names are fixed by the application.
Which versions contain the fix?
The issue is fixed in Action View versions 8.1.4.1 and 8.0.5.2. Versions prior to those releases are described as affected.