CVE-2018-16471: XSS
Last updated 25 August 2025
Other sources
There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Carefully crafted requests can impact the data returned by the scheme method on Rack::Request. Applications that expect the scheme to be limited to 'http' or 'https' and do not escape the return value could be vulnerable to an XSS attack. Note that applications using the normal escaping mechanisms provided by Rails may not impacted, but applications that bypass the escaping mechanisms, or do not use them may be vulnerable.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the vulnerability ID?
The vulnerability ID is CVE-2018-16471.
What is the severity of CVE-2018-16471?
The severity of CVE-2018-16471 is medium with a severity value of 6.1.
How does CVE-2018-16471 affect Rack?
CVE-2018-16471 affects Rack versions before 2.0.6 and 1.6.11.
What is the impact of CVE-2018-16471?
CVE-2018-16471 allows carefully crafted requests to impact the data returned by the `scheme` method on `Rack::Request`, potentially leading to XSS vulnerabilities.
How do I fix CVE-2018-16471?
To fix CVE-2018-16471, update Rack to version 2.0.6 or 1.6.11 or later.