CVE-2026-117645
Phoenix.HTML vulnerable to attribute injection via unvalidated attribute names in attributes_escape/1
- State
- Published
- Severity
- 5.3 Medium
- Published
- Oct 30, 2026
- Updated
- Oct 30, 2026
- Reserved
- Oct 30, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.3 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | EEF |
Weaknesses
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Products
| Product | Versions |
|---|---|
phoenix_htmlphoenixframework |
|
phoenix_htmlphoenixframework |
|
References
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