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fix(dynamic-field): escape media field value (stored XSS) #1029

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Merged
mmcintosh merged 2 commits into from
Aug 19, 2026
Merged

fix(dynamic-field): escape media field value (stored XSS) #1029

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bcc2d3b
fix(dynamic-field): escape media field VALUE against stored XSS
mmcintosh Jul 23, 2026
5162de4
Merge remote-tracking branch 'origin/main' into fix/dynamic-field-med…
mmcintosh Aug 17, 2026
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29 changes: 24 additions & 5 deletions packages/core/src/templates/components/dynamic-field.template.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -891,14 +891,14 @@ export function renderDynamicField(field: FieldDefinition, options: FieldRenderO
const renderMediaPreview = (url: unknown, alt: string, classes: string) => {
if (typeof url !== 'string' || url === '') return ''
if (isVideoUrl(url)) {
return `<video src="${url}" class="${classes}" muted></video>`
return `<video src="${escapeHtml(url)}" class="${classes}" muted></video>`
}
return `<img src="${url}" alt="${alt}" class="${classes}">`
return `<img src="${escapeHtml(url)}" alt="${escapeHtml(alt)}" class="${classes}">`
}

fieldHTML = `
<div class="media-field-container">
<input type="hidden" id="${fieldId}" name="${fieldName}" value="${isMultiple ? mediaValues.join(',') : singleValue}" data-multiple="${isMultiple}">
<input type="hidden" id="${fieldId}" name="${fieldName}" value="${escapeHtml(String(isMultiple ? mediaValues.join(',') : singleValue))}" data-multiple="${isMultiple}">

${
isMultiple
Expand All @@ -907,11 +907,11 @@ export function renderDynamicField(field: FieldDefinition, options: FieldRenderO
${mediaValues
.map(
(url: string, idx: number) => `
<div class="relative media-preview-item" data-url="${url}">
<div class="relative media-preview-item" data-url="${escapeHtml(url)}">
${renderMediaPreview(url, `Media ${idx + 1}`, 'w-full h-24 object-cover rounded-lg border border-white/20')}
<button
type="button"
onclick="removeMediaFromMultiple('${fieldId}', '${url}')"
onclick="removeMediaFromMultiple('${fieldId}', '${escapeJsAttr(url)}')"
data-media-remove="true"
class="absolute top-1 right-1 bg-red-600 text-white rounded-full p-1 hover:bg-red-700"
${disabled ? 'disabled' : ''}
Expand Down Expand Up @@ -2648,3 +2648,22 @@ function escapeHtml(text: string): string {
"'": '&#39;'
}[char] || char))
}

/**
* Escape a string for a single-quoted JS string inside an HTML attribute —
* e.g. onclick="f('${escapeJsAttr(x)}')". escapeHtml is insufficient: the browser
* HTML-decodes the attribute BEFORE the inline script parses, so &#39; decodes back
* to ' and terminates the string. Emits \xHH escapes so no raw '"<>&\ survives.
*/
function escapeJsAttr(value: unknown): string {
return String(value ?? '').replace(/[\\'"<>&\r\n]/g, (ch) => ({
'\\': '\\\\',
"'": '\\x27',
'"': '\\x22',
'<': '\\x3C',
'>': '\\x3E',
'&': '\\x26',
'\r': '\\r',
'\n': '\\n'
}[ch] || ch))
}
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