CVE Catalog

CVE-2026-117645

MediumCVSS 5.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.32%

24th percentile - higher than 24% of all known CVEs

Summary

phoenix_html is vulnerable to cross-site scripting (XSS) due to improper neutralization of input during web page generation. The attributes_escape/1 function in lib/phoenix_html.ex escapes attribute values but not attribute names; a key such as 'x onmouseover' can end the attribute and start a new one, and atom keys are only dasherized, allowing any character including quotes and '>'. The issue affects versions from 1.0.0 before 3.3.5 and from 4.0.0 before 4.4.0.

Risk Assessment

An attacker could inject malicious attributes and scripts into rendered HTML, potentially leading to JavaScript execution in the user's browser and theft of session data. The risk occurs when an application builds attribute names from untrusted input.

Recommendation

Update phoenix_html to version 3.3.5 or 4.4.0 (or later). Ensure attribute names are not built from untrusted input.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS