CVE-2026-54603
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure.
- Exploit odds
- 0.4% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.4% in the next 30 days (EPSS).
- Severity: 8.6 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.4% · EPSS, next 30 days
- Weakness
- CWE-200 · Information exposure
- Record status
- Awaiting Analysis
Attack profile CVSS 3.1 · 8.6
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-54603.md and follow it. Check whether this project is affected by CVE-2026-54603. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/ruby-oauth/oauth2/commit/0f0a474f1b38453e119e660c2daca742d4378ce9
- https://github.com/ruby-oauth/oauth2/releases/tag/v2.0.22
- https://github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2-gfv9
- https://github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2-gfv9
References
- https://github.com/ruby-oauth/oauth2/commit/0f0a474f1b38453e119e660c2daca742d4378ce9
- https://github.com/ruby-oauth/oauth2/releases/tag/v2.0.22
- https://github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2-gfv9
- https://lists.debian.org/debian-lts-announce/2026/10/msg00014.html
- https://github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2-gfv9