Budibase/budibase · error · ActiveContentFileError

File " " contains active content which is not permitted

Error message

File "${fileName}" contains active content which is not permitted

What it means

Thrown as ActiveContentFileError by uploadFile when the file's extension is in ACTIVE_CONTENT_EXTENSIONS (html, htm, js, mjs, svg, wasm, xhtml, etc.). These types can execute scripts when served, enabling stored XSS, so they are rejected regardless of role or environment.

Solutions

1. Rename/convert to a safe format (SVG logo -> PNG, HTML report -> PDF)
2. Zip the active-content files and upload the archive instead
3. Serve the active content from a dedicated static host/CDN outside Budibase

Example fix

// before
upload 'logo.svg' as attachment
// after
export and upload 'logo.png'

const ACTIVE = new Set(['html','htm','js','jse','mjs','svg','svgz','wasm','xhtml','mhtml','shtml'])
function isNotActiveContent(name) {
  return !ACTIVE.has((name.split('.').pop() || '').toLowerCase())
}

const isActiveContentFile = (name: string): boolean =>
  ['html','htm','js','jse','mjs','svg','svgz','wasm','xhtml','mhtml','shtml'].includes((name.split('.').pop() || '').toLowerCase())

try {
  await api.uploadFile(fd)
} catch (err) {
  if (err instanceof ActiveContentFileError) {
    // convert to a safe format (PNG/PDF) and retry
  } else throw err
}

When it happens

Trigger: Uploading any file whose extension is html/js/svg/wasm and similar active content types to the attachment upload endpoint.

Common situations: Teams trying to attach HTML reports, SVG logos, or JS bundles as app attachments; hosting a static site's assets inside Budibase attachments.

Related errors

• File " " has an invalid extension
• File " " has no extension, an extension is required to…
• Attempted to upload a file without a filename
• Attempted to upload a file without a path
• Cannot reset password.

AI-assisted analysis of Budibase/budibase@a81a902e9a (2026-08-29). Data as JSON: /api/errors/8d4a47ee4fb989f5. Report an issue: GitHub.

Appendix: source

Thrown at packages/server/src/api/controllers/static/index.ts:294

        )
      }

      const extensionLower = extension.toLowerCase()
      const isPublicUser =
        ctx.roleId === roles.BUILTIN_ROLE_IDS.PUBLIC ||
        ctx.user?.roleId === roles.BUILTIN_ROLE_IDS.PUBLIC
      const enforceInvalidExtension = isPublicUser || !env.SELF_HOSTED
      if (
        enforceInvalidExtension &&
        InvalidFileExtensions.includes(extensionLower)
      ) {
        throw new BadRequestError(
          `File "${fileName}" has an invalid extension: "${extension}"`
        )
      }

      if (ACTIVE_CONTENT_EXTENSIONS.has(extensionLower)) {
        throw new ActiveContentFileError(fileName)
      }

      const mimeType =
        typeof rawMimeType === "string" ? rawMimeType.toLowerCase() : undefined
      if (
        mimeType &&
        ACTIVE_CONTENT_MIME_TYPES.some(type => mimeType.includes(type))
      ) {
        throw new ActiveContentFileError(fileName)
      }

      if (
        filePath &&
        (typeof filePath === "string" || Buffer.isBuffer(filePath)) &&
        (await detectActiveContent(filePath))
      ) {
        throw new ActiveContentFileError(fileName)
      }

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