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.

The remote Debian 12 host has a package installed that is affected by a vulnerability as referenced in the dla-4822 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4822-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                        Simon Quigley     October 05, 2026                              https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : ruby-oauth2     Version        : 1.4.4-1+deb12u1     CVE ID         : CVE-2026-54603

    A vulnerability was discovered in ruby-oauth2, a Ruby library for     OAuth 2.0, which could result in a bearer token being sent to the     host named by a redirect Location.

    For Debian 12 bookworm, this problem has been fixed in version     1.4.4-1+deb12u1.

    We recommend that you upgrade your ruby-oauth2 packages.

    For the detailed security status of ruby-oauth2 please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/ruby-oauth2

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-54603)

Note that Nessus relies on the presence of the package as reported by the vendor.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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. (CVE-2026-54603)

ID	Name	Product	Family	Type	Severity
363013	Debian dla-4822 : ruby-oauth2 - security update	Nessus	Debian Local Security Checks	Local	high
330643	Linux Distros Unpatched Vulnerability : CVE-2026-54603	Nessus	Misc.	Local	high
445400	SCA: security update for oauth2 (GHSA-pp92-crg2-gfv9)	Tenable Cloud Security	SCA Checks	Local	high
445400	SCA: security update for oauth2 (GHSA-pp92-crg2-gfv9)	Tenable Self-Hosted Container Security	SCA Checks	Local	high

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CVE-2026-54603

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Tenable Plugins

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