CVE-2025-59430

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
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=.

Reporters

• Amine zwxxb Elsassi of Aptos Labs

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.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2025-59430 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.3.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-59430? CVE-2025-59430 is a high-severity cross-site scripting (XSS) vulnerability in @meshconnect/web-link-sdk (npm), affecting versions < 3.3.2. It is fixed in 3.3.2. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2025-59430? CVE-2025-59430 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of @meshconnect/web-link-sdk are affected by CVE-2025-59430? @meshconnect/web-link-sdk (npm) versions < 3.3.2 is affected.
4. Is there a fix for CVE-2025-59430? Yes. CVE-2025-59430 is fixed in 3.3.2. Upgrade to this version or later.
5. Is CVE-2025-59430 exploitable, and should I be worried? Whether CVE-2025-59430 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-59430 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-59430? Upgrade @meshconnect/web-link-sdk to 3.3.2 or later.