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rules(js): add balanced innerHTML/outerHTML DOM XSS rule #65

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rules(js): add balanced innerHTML/outerHTML DOM XSS rule #65

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86f0310
rules(js): add balanced innerHTML/outerHTML DOM XSS rule
cursoragent Jul 30, 2026
f8f4c14
scanner: recognize escapeHTML/sanitizeHtml as HTML sanitizers
cursoragent Jul 30, 2026
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24 changes: 24 additions & 0 deletions rules/javascript/frontend_security.ron
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,30 @@
file_types: Some((extensions: Some([".js", ".jsx", ".ts", ".tsx"]))),
tags: Some(["xss", "dom", "frontend", "cwe-79"])
),
(
id: Some("js-dom-xss-innerhtml-001"),
name: Some("DOM XSS via dynamic innerHTML/outerHTML assignment"),
category: Some("xss"),
mode: "search",
// The leading `^[^=;{]*` keeps a match anchored to the assignment that starts the
// matched node, so enclosing blocks are not reported instead of the sink line.
patterns: Some([
// Interpolated template literal: el.innerHTML = `<b>${value}</b>`
"regex:^[^=;{]*\\.(innerHTML|outerHTML)\\b[^=]*=[^=][\\s\\S]*\\$\\{",
// HTML markup concatenated with an expression:
// el.innerHTML = '<b>' + value / el.innerHTML = value + '</b>'
"regex:^[^=;{]*\\.(innerHTML|outerHTML)\\b[^=]*=[^=][\\s\\S]*(['\"`]\\s*\\+\\s*[A-Za-z_$]|[A-Za-z_$][\\w$]*\\s*\\+\\s*['\"`])",
// Non-literal value: el.innerHTML = value / render(value), el.innerHTML += value
"regex:^[^=;{]*\\.(innerHTML|outerHTML)\\b[^=]*=\\s*[A-Za-z_$]"
]),
finding_type: Some("DOM XSS"),
severity: Some("High"),
confidence: Some("Medium"),
cwe_id: Some("cwe-79"),
description: Some("innerHTML/outerHTML is assigned a value the scanner cannot prove is static HTML, so attacker-controlled markup can execute; assign textContent or sanitize with DOMPurify instead"),
file_types: Some((extensions: Some([".js", ".jsx", ".ts", ".tsx"]))),
tags: Some(["xss", "dom", "frontend", "cwe-79"])
),
(
id: Some("js-react-dangerously-set-inner-html-001"),
name: Some("React DOM XSS via dangerouslySetInnerHTML"),
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12 changes: 10 additions & 2 deletions src/scanner/utils.rs
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Expand Up @@ -606,8 +606,16 @@ impl AstUtils {
}

fn check_html_sanitization(code: &str) -> bool {
let html_sanitizers =
["DOMPurify.sanitize(", "validator.escape(", "xss(", "escapeHtml(", "encodeHTML("];
let html_sanitizers = [
"DOMPurify.sanitize(",
"validator.escape(",
"xss(",
"escapeHtml(",
"escapeHTML(",
"encodeHTML(",
"sanitizeHtml(",
"sanitizeHTML(",
];
html_sanitizers.iter().any(|pat| code.contains(pat))
}

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