XSS in Rack

CVE-2018-16471

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.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.019 (77.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2018-16471?
CVE-2018-16471 is a medium-severity vulnerability in Rack, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-11-13.
How severe is CVE-2018-16471?
Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2018-16471 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.