CVE-2017-7559: Red Hat Undertow

Medium severity, CVSS 6.1. EPSS: 1.9% chance of exploitation in the next 30 days.

In Undertow 2.x before 2.0.0.Alpha2, 1.4.x before 1.4.17.Final, and 1.3.x before 1.3.31.Final, it was found that the fix for CVE-2017-2666 was incomplete and invalid characters are still allowed in the query string and path parameters. This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation, to inject data into the HTTP response. By manipulating the HTTP response the attacker could poison a web-cache, perform an XSS attack, or obtain sensitive information from requests other than their own.

Affected products

• Red Hat Undertow: from 1.3.0, before 1.3.31 (fixed in 1.3.31); from 1.4.0, before 1.4.17 (fixed in 1.4.17); version 2.0.0 only

Published 2018-01-10. Last modified 2026-06-17.