GHSA-h3pq-667x-r789
Plate media plugins has a XSS in media embed element when using custom URL parsers
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @udecode/plate-media | < 36.0.10 | 36.0.10 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Impact
Editors that use `MediaEmbedElement` and pass custom `urlParsers` to the `useMediaState` hook may be vulnerable to XSS if a custom parser allows `javascript:`, `data:` or `vbscript:` URLs to be embedded. Editors that do not use `urlParsers` and instead consume the `url` property directly may also be vulnerable if the URL is not sanitised.
The default parsers `parseTwitterUrl` and `parseVideoUrl` are not affected.
Examples of vulnerable code:
```tsx
const { embed } = useMediaState({
urlParsers: [
// Custom parser that does not use an allowlist or validate the URL protocol
(url) => ({ url }),
],
});
return (
<iframe
src={embed!.url}
// ...
/>
);
```
```tsx
const { url } = useMediaState();
return (
<iframe
// url property used directly from useMediaState() with no sanitisation
src={url}
// ...
/>
);
```
```tsx
const { url } = element;
return (
<iframe
// url property used directly from element with no sanitisation
src={url}
// ...
/>
);
```
### Patches
`@udecode/plate-media` 36.0.10 resolves this issue by only allowing HTTP and HTTPS URLs during parsing. This affects only the `embed` property returned from `useMediaState`.
In addition, the `url` property returned from `useMediaState` has been renamed to `unsafeUrl` to indicate that it has not been sanitised. The `url` property on `element` is also unsafe, but has not been renamed. If you're using either of these properties directly, you will still need to validate the URL yourself.
### Workarounds
Ensure that any custom `urlParsers` do not allow `javascript:`, `data:` or `vbscript:` URLs to be returned in the `url` property of their return values.
If `url` is consumed directly, validate the URL protocol before passing it to the `iframe` element.
### References
How to verify the protocol of a URL: https://stackoverflow.com/a/43467144
References
External links from the advisory. They lead to third-party sites.