GHSA-xcxh-6cv4-q8p8 — hfs
Fix: rejetto/hfs@6531bcdGHSA-xcxh-6cv4-q8p8 is a security vulnerability in hfs. A fix is available for hfs — see the affected versions and patch details below.
HFS user adding a "web link" in HFS is vulnerable to "target=_blank" exploit
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.
hfsnpmDescription
Summary
When adding a "web link" to the HFS virtual filesystem, the frontend opens it with target="_blank" but without the rel="noopener noreferrer" attribute. This allows the opened page to use the window.opener property to change the location of the original HFS tab.
Details
While most modern browsers have fixes already implemented for this target="_blank" exploit at the browser level, users on outdated browsers remain vulnerable. This means that if an admin of the HFS instance adds a link to an external third-party service (that they believe is safe at the time) and that service they added later becomes compromised, the malicious page could replace the original HFS tab's content with a phishing page. This does not require the admin account itself to be compromised, only that a legitimate linked site turns malicious.
Impact
Affected users (people using old browsers without the browser level fix) could be misled into entering their HFS credentials or other sensitive information into a fake site controlled by an attacker. This vulnerability is fixed in most modern browsers, but adding rel="noopener noreferrer" remains a best practice to protect legacy environments.
PoC
Firstly, in the HFS admin page, under the filesystem (/~/admin/#/fs) press "Add" then "web link" then set the link to take the user to to an HTML file that exploits this vulnerability, here is an example of a malicious HTML file's code:
<body>
<script>
window.opener.location = "https://example.org";
</script>
<b>Error loading...</b>
</body>
</html>
Now, in the HFS folder you placed this web link in, open HFS and click the web link, if you aren't on a modern browser that fixed this vulnerability on the browser level, then switch back to the HFS tab that opened it, and you should be taken to "https://example.org" if you tried the code I provided, or whatever other page you tried.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | hfs | all versions | 0.57.10npm install hfs@0.57.10 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hfs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hfs to 0.57.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xcxh-6cv4-q8p8 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-xcxh-6cv4-q8p8 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-xcxh-6cv4-q8p8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-xcxh-6cv4-q8p8 in your dependencies?
O3 Security finds GHSA-xcxh-6cv4-q8p8 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.