Vulnerability Description
Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21 and 3.2.0 to before 3.2.6, 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 can be interpreted by Rack as multiple Forwarded directives rather than as a single quoted for value. In deployments where an upstream proxy, WAF, or intermediary validates or preserves quoted Forwarded values differently, this discrepancy can allow an attacker to smuggle host, proto, for, or by parameters through a single header value. This issue has been patched in versions 3.1.21 and 3.2.6.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Rack | Rack | >= 3.0.0, < 3.1.21 |
Related Weaknesses (CWE)
References
- https://github.com/rack/rack/security/advisories/GHSA-qfgr-crr9-7r49Vendor AdvisoryMitigation
FAQ
What is CVE-2026-32762?
CVE-2026-32762 is a vulnerability with a CVSS score of 4.8 (MEDIUM). Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21 and 3.2.0 to before 3.2.6, Rack::Utils.forwarded_values parses the RFC 7239 Forwarded header by splitting on sem...
How severe is CVE-2026-32762?
CVE-2026-32762 has been rated MEDIUM with a CVSS base score of 4.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-32762?
Check the references section above for vendor advisories and patch information. Affected products include: Rack Rack.