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.
Project Subscriptions
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Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-qfgr-crr9-7r49 | Rack: Forwarded Header semicolon injection enables Host and Scheme spoofing |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 02 Apr 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Rack: Forwarded Header semicolon injection enables Host and Scheme spoofing | |
| Weaknesses | CWE-436 | |
| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-04-02T17:42:42.305Z
Reserved: 2026-03-13T18:53:03.533Z
Link: CVE-2026-32762
Updated: 2026-04-02T17:42:37.595Z
Status : Received
Published: 2026-04-02T18:16:27.730
Modified: 2026-04-02T18:16:27.730
Link: CVE-2026-32762
No data.
OpenCVE Enrichment
No data.
Weaknesses
Github GHSA