Summary
HFS user adding a "web link" in HFS is vulnerable to "target=_blank" exploit
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.
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.
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.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-XCXH-6CV4-Q8P8? GHSA-XCXH-6CV4-Q8P8 is a low-severity security vulnerability in hfs (npm), affecting versions <= 0.57.9. It is fixed in 0.57.10.
- Which versions of hfs are affected by GHSA-XCXH-6CV4-Q8P8? hfs (npm) versions <= 0.57.9 is affected.
- Is there a fix for GHSA-XCXH-6CV4-Q8P8? Yes. GHSA-XCXH-6CV4-Q8P8 is fixed in 0.57.10. Upgrade to this version or later.
- Is GHSA-XCXH-6CV4-Q8P8 exploitable, and should I be worried? Whether GHSA-XCXH-6CV4-Q8P8 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
- What actually determines whether GHSA-XCXH-6CV4-Q8P8 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.
- How do I fix GHSA-XCXH-6CV4-Q8P8? Upgrade
hfsto 0.57.10 or later.