CVE-2026-126079 Action View: Possible XSS vulnerability in Action View text helpers
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-126079?
CVE-2026-126079 is a medium-severity vulnerability in rails, published on 10 Nov 2026.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-126079?
2 open source packages ship an affected version, including actionview.
| Package | Affected | Fixed in |
|---|---|---|
actionview RubyGems | All versions | 8.0.5.2 |
actionview RubyGems | From 8.1.0.beta1 | 8.1.4.1 |
How do I fix CVE-2026-126079?
Upgrade actionview to a fixed version for your release line: 8.0.5.2 or 8.1.4.1.
Is CVE-2026-126079 being exploited?
There is no known exploitation of CVE-2026-126079 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-126079, GHSA-2p2f-4rq4-gjwc, UBUNTU-CVE-2026-126079.