CVE-2026-117645
Phoenix.HTML vulnerable to attribute injection via unvalidated attribute names in attributes_escape/1
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in phoenixframework phoenix_html allows an attacker who controls attribute names to inject attributes and script into rendered HTML via Phoenix.HTML.attributes_escape/1. attributes_escape/1 in lib/phoenix_html.ex escapes attribute values but not attribute names. key_escape/1 passes a binary key through html_escape, which neutralizes quotes and angle brackets but not whitespace, so a key such as x onmouseover ends the attribute and starts a new one. An atom key is only dasherized, so any character passes, including quotes and >. Nested data, aria and phx keys take the same paths. An application is affected when it builds attribute keys from untrusted input and renders them through HEEx <tag {@attrs}>, content_tag/3, or a direct call. Before 3.0.0 the same code lived in Phoenix.HTML.Tag. This issue affects phoenix_html: from 1.0.0 before 3.3.5 and from 4.0.0 before 4.4.0.
| CWE | CWE-79 |
| Vendor | phoenixframework |
| Product | phoenix_html |
| Published | Oct 30, 2026 |
Get instant alerts for phoenixframework phoenix_html
Be the first to know when new unknown vulnerabilities affecting phoenixframework phoenix_html are published — delivered to Slack, Telegram or Discord.