CVE-2025-59430 is a high-severity (CVSS 8.2) Cross-site Scripting (XSS) vulnerability in @meshconnect/web-link-sdk. A fix is available for @meshconnect/web-link-sdk — see the affected versions and patch details below.
Mesh Connect JS SDK Vulnerable to Cross Site Scripting via createLink.openLink
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-59430.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@meshconnect/web-link-sdknpmDescription
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
- Extract poc-mesh-web-sdk.zip
- Run
yarn installand thenyarn start - Paste this payload inside the input box:
amF2YXNjcmlwdDphbGVydCh3aW5kb3cucGFyZW50LmRvY3VtZW50LmJvZHkuZ2V0RWxlbWVudHNCeVRhZ05hbWUoImgyIikuaXRlbSgwKVsiaW5uZXJIVE1MIl0pLy8= - Click on the OpenLink button
- Notice the alert box and ability to access the
h2title 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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @meshconnect/web-link-sdk | all versions | 3.3.2npm install @meshconnect/web-link-sdk@3.3.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @meshconnect/web-link-sdk, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @meshconnect/web-link-sdk to 3.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59430 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2025-59430 in your dependencies?
Find it across npm, including transitive dependencies.