CVE-2026-54603

OAuth2::Client#request: Protocol-relative redirect Location overrides authority, leaking bearer Authorization to attacker host

State: Published
Severity: 8.6 High
Published: Jul 28, 2026
Updated: Oct 5, 2026
Reserved: Jun 15, 2026

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Description

OAuth2 is a Ruby wrapper for the OAuth 2.0 and 2.1 authorization frameworks, including OpenID Connect (OIDC). From 0.4.0 to 2.0.21, a protocol-relative redirect Location returned to OAuth2::Client#request overrides the request authority, so the bearer Authorization header is sent to an attacker-controlled host, leaking the credential. This issue is fixed in version 2.0.22.

Scores

CVSS	Score	Vector	Source
3.1	8.6 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N	GitHub_M

Weaknesses

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-601 URL Redirection to Untrusted Site ('Open Redirect')

Affected Products

Product	Versions
oauth2ruby-oauth	>= 0.4.0, < 2.0.22Affected

References

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