PT-2026-29844 · Rack · Rack

Th4S1S · Published 2026-04-02 · Updated 2026-04-02 · CVE-2026-32762

NVD

CVSS v3.1

4.8

Medium

AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

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.

Fix

Weakness Enumeration

CWE-436

Related Identifiers

CVE-2026-32762

Affected Products

Rack

References · 2

• https://nvd.nist.gov/vuln/detail/CVE-2026-32762 · Security Note
• https://github.com/rack/rack/security/advisories/GHSA-qfgr-crr9-7r49 · Note