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Potential fix for code scanning alert no. 22: Client-side cross-site scripting #86

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Merged
EthanThePhoenix38 merged 1 commit into from
Feb 14, 2026
Merged

Potential fix for code scanning alert no. 22: Client-side cross-site scripting #86

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18 changes: 15 additions & 3 deletions docs.html
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Original file line number Diff line number Diff line change
Expand Up @@ -307,6 +307,17 @@ <h4>On this page</h4>
return text.toLowerCase().replace(/[^\w]+/g, '-').replace(/^-|-$/g, '');
}

// Basic HTML escaping to prevent XSS when inserting untrusted values
function escapeHtml(str) {
return String(str)
.replace(/&/g, '&amp;')
.replace(/</g, '&lt;')
.replace(/>/g, '&gt;')
.replace(/"/g, '&quot;')
.replace(/'/g, '&#39;')
.replace(/\//g, '&#x2F;');
}

// Simple markdown to HTML parser with anchor generation
function parseMarkdown(md) {
let html = md;
Expand Down Expand Up @@ -389,10 +400,11 @@ <h4>On this page</h4>

// Fetch and display documentation
async function loadDoc(filename) {
const safeFilename = escapeHtml(filename);
Comment on lines 402 to +403
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Copilot AI Feb 14, 2026

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While HTML escaping prevents XSS in the displayed content, the filename parameter still comes from user-controlled input (window.location.hash via init()) without validation. Consider adding explicit validation at the start of this function to ensure the filename matches one of the allowed documents. For example, you could define an allowlist of valid filenames (TECHNIQUE.md, READER_MODE_PLAN.md, SUPABASE_MIGRATION.md, ACTION_README.md) and reject any filename that's not in the list. This would provide defense in depth against potential SSRF or path traversal issues when constructing the GitHub API URL on line 413.

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docsContent.innerHTML = `
<div class="loading-docs">
<div class="loading-spinner"></div>
<p>Loading ${filename}...</p>
<p>Loading ${safeFilename}...</p>
</div>
`;

Expand All @@ -417,9 +429,9 @@ <h4>On this page</h4>
console.error('Error loading doc:', error);
docsContent.innerHTML = `
<h1>Error Loading Documentation</h1>
<p>Failed to load ${filename}. Please try again later.</p>
<p>Failed to load ${safeFilename}. Please try again later.</p>
<p style="margin-top: 20px;">
<a href="https://github.com/${DOCS_CONFIG.owner}/${DOCS_CONFIG.repo}/blob/${DOCS_CONFIG.branch}/${DOCS_CONFIG.docsPath}/${filename}" target="_blank">
<a href="https://github.com/${DOCS_CONFIG.owner}/${DOCS_CONFIG.repo}/blob/${DOCS_CONFIG.branch}/${DOCS_CONFIG.docsPath}/${safeFilename}" target="_blank">
View on GitHub
</a>
</p>
Expand Down