CVE-2026-54603

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 63% of all CVEs by exploit prediction. 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: epss, secondary
Elevated
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.6Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.6
EG Score
8.6(medium)
EG Risk
70(Attend)
EG Risk 70/100SSVC: Attend

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 computed
Severity86% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

July 28, 2026

Last Modified

September 9, 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/v2.0.22
github_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/0f0a474f1b38453e119e660c2daca742d4378ce9
github 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-gfv9

Vendor 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.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
ruby-oauth21.4.4-1 ... 2.0.9-1 (6 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
ruby-oauth21.4.4-1 ... 2.0.9-1 (7 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
ruby-oauth22.0.17-1, 2.0.18-1, 2.0.25-1, 2.0.9-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
ruby-oauth22.0.17-1, 2.0.18-1, 2.0.9-12.0.25-1—
RubyGems(1)
PackageVulnerable rangeFixed inDependents
oauth20.4.0 ... 2.0.9 (58 versions)2.0.22—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 49× 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.

  1. 2026-09-15 08:38 UTCEG score recompute
  2. 2026-09-15 03:11 UTCEPSS rescore
  3. 2026-09-13 20:20 UTCEG score recompute
  4. 2026-09-13 16:47 UTCEPSS rescore
  5. 2026-09-12 17:59 UTCEG score recompute
  6. 2026-09-11 15:22 UTCEG score recompute
  7. 2026-09-11 14:53 UTCEPSS rescore
  8. 2026-09-10 10:15 UTCEG score recompute
  9. 2026-09-10 09:35 UTCEPSS rescore
  10. 2026-09-09 08:01 UTCEG score recompute
  11. 2026-09-08 22:01 UTCEPSS rescore
  12. 2026-09-07 20:55 UTCEG score recompute
  13. 2026-09-07 16:01 UTCEPSS rescore
  14. 2026-09-06 23:14 UTCEG score recompute
  15. 2026-09-06 13:47 UTCEPSS rescore
  16. 2026-09-05 19:10 UTCEG score recompute
  17. 2026-09-05 05:31 UTCEG score recompute
  18. 2026-09-04 12:01 UTCEG score recompute
  19. 2026-09-04 05:06 UTCEPSS rescore
  20. 2026-09-02 14:12 UTCEPSS rescore
  21. 2026-09-01 22:52 UTCEG score recompute
  22. 2026-09-01 13:54 UTCEPSS rescore
  23. 2026-09-01 04:40 UTCEPSS rescore
  24. 2026-08-31 01:53 UTCEG score recompute
  25. 2026-08-30 19:17 UTCEPSS rescore
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  1. 2026-08-30 12:44 UTCEG score recompute
  2. 2026-08-30 01:22 UTCEPSS rescore
  3. 2026-08-29 23:31 UTCEG score recompute
  4. 2026-08-28 21:41 UTCEPSS rescore
  5. 2026-08-27 20:57 UTCEG score recompute
  6. 2026-08-27 14:25 UTCEPSS rescore
  7. 2026-08-26 15:10 UTCEG score recompute
  8. 2026-08-26 14:46 UTCEPSS rescore
  9. 2026-08-26 02:01 UTCEG score recompute
  10. 2026-08-25 13:49 UTCEPSS rescore
  11. 2026-08-24 23:41 UTCEG score recompute
  12. 2026-08-24 10:32 UTCEG score recompute
  13. 2026-08-23 08:11 UTCEG score recompute
  14. 2026-08-23 00:19 UTCEPSS rescore
  15. 2026-08-22 05:53 UTCEG score recompute
  16. 2026-08-21 23:49 UTCEPSS rescore
  17. 2026-08-21 03:35 UTCEG score recompute
  18. 2026-08-20 22:55 UTCEPSS rescore
  19. 2026-08-20 00:55 UTCEG score recompute
  20. 2026-08-19 17:04 UTCEPSS rescore
  21. 2026-08-18 22:18 UTCEG score recompute
  22. 2026-08-18 13:48 UTCEPSS rescore
  23. 2026-08-17 19:56 UTCEG score recompute
  24. 2026-08-17 13:47 UTCEPSS rescore
  25. 2026-08-16 16:41 UTCEG score recompute
  26. 2026-08-16 14:56 UTCEPSS rescore
  27. 2026-08-16 03:27 UTCEG score recompute
  28. 2026-08-16 02:14 UTCEPSS rescore
  29. 2026-08-15 14:18 UTCEG score recompute
  30. 2026-08-15 01:30 UTCEPSS rescore
  31. 2026-08-13 22:52 UTCEG score recompute
  32. 2026-08-13 22:00 UTCEPSS rescore
  33. 2026-08-12 20:35 UTCEG score recompute
  34. 2026-08-12 13:51 UTCEPSS rescore
  35. 2026-08-11 18:19 UTCEG score recompute
  36. 2026-08-11 05:05 UTCEG score recompute
  37. 2026-08-11 00:00 UTCEPSS rescore
  38. 2026-08-10 02:35 UTCEG score recompute
  39. 2026-08-09 13:46 UTCEPSS rescore
  40. 2026-08-09 00:19 UTCEG score recompute
  41. 2026-08-08 16:37 UTCEPSS rescore
  42. 2026-08-07 22:01 UTCEG score recompute
  43. 2026-08-06 19:44 UTCEG score recompute
  44. 2026-08-06 13:47 UTCEPSS rescore
  45. 2026-08-06 06:35 UTCEG score recompute
  46. 2026-08-05 19:17 UTCEPSS rescore
  47. 2026-08-05 04:19 UTCEG score recompute
  48. 2026-08-04 15:10 UTCEPSS rescore
  49. 2026-08-04 15:08 UTCEG score recompute
  50. 2026-08-04 10:39 UTCEPSS rescore
  51. 2026-08-03 12:51 UTCEG score recompute
  52. 2026-08-03 10:36 UTCEPSS rescore
  53. 2026-08-02 10:24 UTCEG score recompute
  54. 2026-08-02 02:27 UTCEPSS rescore
  55. 2026-08-01 08:07 UTCEG score recompute
  56. 2026-08-01 04:16 UTCEPSS rescore
  57. 2026-07-30 16:42 UTCEG score recompute
  58. 2026-07-30 16:28 UTCEPSS rescore
  59. 2026-07-30 03:30 UTCEG score recompute
  60. 2026-07-30 01:30 UTCEPSS rescore
  61. 2026-07-29 14:20 UTCEG score recompute
  62. 2026-07-29 13:59 UTCEG score recompute
  63. 2026-07-28 17:22 UTCEG score recompute
  64. 2026-07-28 16:53 UTCEG score recompute
  65. 2026-07-28 16:53 UTCMITRE cvelistV5first tracked

Frequently asked(5)

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, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54603 actively exploited?
CVE-2026-54603 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 63.3% of all scored CVEs.
What is the CVSS score of CVE-2026-54603?
CVE-2026-54603 has a CVSS v3 base score of 8.6 (NVD).
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

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