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
HIGHPre-NVD 8.68.6
EchelonGraph scoreLOW confidence
This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 8.6Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.6
- EG Score
- 8.6(low)
- EG Risk
- 43(Track)EG Risk 43/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity86% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
July 28, 2026
Last Modified
July 28, 2026
Advisory Details (3)
Auto-updated Jul 28, 2026🔬 Proof of concept available. Patch available. Sources: github_release, github, github_commit.
github_release Patch Available
v2.0.22
Patch available: ruby-oauth/oauth2 v2.0.22
https://github.com/ruby-oauth/oauth2/releases/tag/v2.0.22github_commit Patch Available
commit 0f0a474f1b38 (ruby-oauth/oauth2)
Patch available: ruby-oauth/oauth2 v2.0.22 (contains commit 0f0a474f1b38)
https://github.com/ruby-oauth/oauth2/commit/0f0a474f1b38453e119e660c2daca742d4378ce9github Patch Available🟡 PoC Available
Protocol-relative redirect Location overrides authority in OAuth2::Client#request, leaking bearer Authorization to attacker host · Advisory · ruby-oauth/oauth2 · GitHub
https://github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2-gfv9Vendor Advisories for CVE-2026-54603(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-28 17:22 UTCEG score recompute
- 2026-07-28 16:53 UTCEG score recompute
- 2026-07-28 16:53 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-54603?
CVE-2026-54603 is a high vulnerability published on July 28, 2026. 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…
When was CVE-2026-54603 disclosed?
CVE-2026-54603 was first published in the National Vulnerability Database on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-54603?
CVE-2026-54603 has a CVSS v3 base score of 8.6 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-54603?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54603, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-54603
Is Your Infrastructure Affected by CVE-2026-54603?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.