Mesh Connect JS SDK Vulnerable to Cross Site Scripting via createLink.openLink

### Summary The lack of sanitization of URLs protocols in the `createLink.openLink` function enables the execution of arbitrary JavaScript code within the context of the parent page. ### Details https://github.com/FrontFin/mesh-web-sdk/blob/cf013b85ab95d64c63cbe46d6cb14695474924e7/packages/link/src/Link.ts#L441 The `createLink.openLink` function takes base64 encoded links, decodes them, and then sets the resulting string as the `src` attribute of an `iframe`. It’s important to note that the protocol part is not validated, so a payload, which is a valid URL, such as `javascript:alert(document.domain)//`, can be provided to the function. ### PoC 1. Extract [poc-mesh-web-sdk.zip](https://github.com/user-attachments/files/22223079/poc-mesh-web-sdk.zip) 2. Run `yarn install` and then `yarn start` 3. Paste this payload inside the input box: `amF2YXNjcmlwdDphbGVydCh3aW5kb3cucGFyZW50LmRvY3VtZW50LmJvZHkuZ2V0RWxlbWVudHNCeVRhZ05hbWUoImgyIikuaXRlbSgwKVsiaW5uZXJIVE1MIl0pLy8=` 4. Click on the _OpenLink_ button 5. Notice the alert box and ability to access the `h2` title from the parent page It can also be verified via `https://paylink.meshconnect.com/?linkToken=amF2YXNjcmlwdDphbGVydCgpLy8=`. ### Impact This is technically indistinguishable from a real page at the rendering level and allows access to the parent page DOM, storage, session, and cookies. If the attacker can specify `customIframeId`, they can hijack the source of existing iframes. If access to the private key is possible or if transactions are tampered with or initialized, in a wallet context, it can result in a critical impact due to loss of funds scenarios. ### Reporters - [Amine `zwxxb` Elsassi](https://github.com/zwxxb) of [Aptos Labs](https://aptoslabs.com/)

Source published

22 Sep 2025 21:09:27 UTC

Source modified

22 Sep 2025 21:58:19 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N

Publisher rating · HIGH