{"vulnerability": "ghsa-pp92-crg2-gfv9", "sightings": [{"uuid": "0c3a398b-c5da-42e4-b9da-05e41e8d5e75", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "GHSA-pp92-crg2-gfv9", "type": "seen", "source": "https://gist.github.com/alon710/76a4f64bf3e94be3974678cdc55c68d9", "content": "# CVE-2026-54603: CVE-2026-54603: Cross-Origin Credential Leakage and SSRF via Protocol-Relative Redirects in ruby-oauth2\n\n> **CVSS Score:** 8.6\n> **Published:** 2026-07-28\n> **Full Report:** https://cvereports.com/reports/CVE-2026-54603\n\n## Summary\nAn issue in the ruby-oauth2 gem allows unauthenticated attackers to steal OAuth access tokens or perform Server-Side Request Forgery (SSRF) via a protocol-relative URI in HTTP Location redirect headers.\n\n## TL;DR\nThe oauth2 Ruby gem leaks active Authorization bearer tokens to untrusted external hosts when following protocol-relative redirects (starting with //) and enables server-side request forgery.\n\n## Exploit Status: POC\n\n## Technical Details\n\n- **CWE ID**: CWE-200, CWE-601\n- **Attack Vector**: Network (AV:N)\n- **CVSS v3.1 Score**: 8.6 (High)\n- **EPSS Score**: Not Available\n- **Impact**: High (Credential Disclosure / SSRF)\n- **Exploit Status**: Proof-of-Concept\n- **KEV Status**: Not Listed\n\n## Affected Systems\n\n- Ruby applications using the oauth2 gem for OAuth authentication workflows\n- **oauth2**: >= 0.4.0, <= 2.0.21 (Fixed in: `2.0.22`)\n\n## Mitigation\n\n- Upgrade the oauth2 gem to version 2.0.22 or higher\n- Implement client-side header scrubbing during HTTP redirects within application code\n- Deploy network-level egress restrictions to block outbound application requests to arbitrary target IP addresses\n\n**Remediation Steps:**\n1. Open your application's Gemfile and locate the oauth2 dependency entry\n2. Modify the dependency constraint to require version >= 2.0.22\n3. Execute 'bundle update oauth2' to pull and install the patched library release\n4. Run your test suite to ensure OAuth identity provider connections remain stable under the sanitized context\n\n## References\n\n- [GitHub Security Advisory](https://github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2-gfv9)\n- [NVD CVE-2026-54603](https://nvd.nist.gov/vuln/detail/CVE-2026-54603)\n\n\n---\n*Generated by [CVEReports](https://cvereports.com/reports/CVE-2026-54603) - Automated Vulnerability Intelligence*", "creation_timestamp": "2026-07-28T20:31:48.792126Z"}]}