Rack: Forwarded Header semicolon injection enables Host and Scheme spoofing — CVE-2026-32762

Summary

## Summary `Rack::Utils.forwarded_values` parses the RFC 7239 `Forwarded` header by splitting on semicolons before handling quoted-string values. Because quoted values may legally contain semicolons, a header such as: ```http Forwarded: for="127.0.0.1;host=evil.com;proto=https" ``` can be interpreted by Rack as multiple `Forwarded` directives rather than as a single quoted `for` value. In deployments where an…

Product

rubygems: rack

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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