CVE-2026-4634

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.0%, top 93% 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: cna:redhat, epss
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
41.2%
KEV
Not listed

Published

April 2, 2026

Last Modified

July 15, 2026

Advisory Details (6)

Auto-updated Jul 3, 2026
Patch available. Sources: redhat.
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:6478
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:6477
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:6476
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:6475
redhat

2450250 – (CVE-2026-4634) CVE-2026-4634 keycloak: Keycloak: Denial of Service via excessive processing of OpenID Connect scope parameters

https://bugzilla.redhat.com/show_bug.cgi?id=2450250
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-4634

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhbk/keycloak-rhel9-operator:26.2-182026-04-02redhat
redhatrhbk/keycloak-rhel92026-04-02redhat
redhatrhbk/keycloak-rhel9-operator:26.4-142026-04-02redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.keycloak:keycloak-services1.0-alpha-1 ... 9.0.3 (223 versions)26.5.7—

Weakness Classification(1)

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

All Vendor Advisories

(4)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 37× 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. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:25 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 14:31 UTCEPSS rescore
  6. 2026-07-19 02:29 UTCEPSS rescore
  7. 2026-07-18 10:04 UTCEPSS rescore
  8. 2026-07-16 17:03 UTCEPSS rescore
  9. 2026-07-15 16:57 UTCEPSS rescore
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 02:00 UTCEPSS rescore
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-13 22:31 UTCEPSS rescore
  14. 2026-07-13 06:13 UTCEPSS rescore
  15. 2026-07-13 06:13 UTCEPSS rescore
  16. 2026-07-12 05:46 UTCEPSS rescore
  17. 2026-07-11 08:27 UTCEPSS rescore
  18. 2026-07-11 08:27 UTCEPSS rescore
  19. 2026-07-09 19:10 UTCEPSS rescore
  20. 2026-07-08 15:16 UTCEPSS rescore
  21. 2026-07-07 13:46 UTCEPSS rescore
  22. 2026-07-06 16:27 UTCEPSS rescore
  23. 2026-07-06 02:23 UTCEPSS rescore
  24. 2026-07-05 02:30 UTCEPSS rescore
  25. 2026-07-04 06:31 UTCEPSS rescore
Show 71 more
  1. 2026-07-01 15:07 UTCEPSS rescore
  2. 2026-06-30 23:22 UTCEPSS rescore
  3. 2026-06-29 14:06 UTCEPSS rescore
  4. 2026-06-29 14:06 UTCEPSS rescore
  5. 2026-06-28 14:07 UTCEPSS rescore
  6. 2026-06-28 04:56 UTCEPSS rescore
  7. 2026-06-28 04:56 UTCEPSS rescore
  8. 2026-06-27 03:08 UTCEPSS rescore
  9. 2026-06-25 13:49 UTCEPSS rescore
  10. 2026-06-24 14:05 UTCEPSS rescore
  11. 2026-06-23 21:33 UTCEPSS rescore
  12. 2026-06-23 21:33 UTCEPSS rescore
  13. 2026-06-22 14:25 UTCEPSS rescore
  14. 2026-06-22 14:25 UTCEPSS rescore
  15. 2026-06-21 14:56 UTCEPSS rescore
  16. 2026-06-21 14:56 UTCEPSS rescore
  17. 2026-06-21 01:59 UTCEPSS rescore
  18. 2026-06-21 01:59 UTCEPSS rescore
  19. 2026-06-19 19:26 UTCEPSS rescore
  20. 2026-06-19 19:26 UTCEPSS rescore
  21. 2026-06-18 17:52 UTCEPSS rescore
  22. 2026-06-18 17:52 UTCEPSS rescore
  23. 2026-06-17 17:53 UTCEPSS rescore
  24. 2026-06-16 17:53 UTCEPSS rescore
  25. 2026-06-15 17:49 UTCEPSS rescore
  26. 2026-06-15 17:49 UTCEPSS rescore
  27. 2026-06-14 23:18 UTCEPSS rescore
  28. 2026-06-13 23:00 UTCEPSS rescore
  29. 2026-06-12 23:12 UTCEPSS rescore
  30. 2026-06-12 23:12 UTCEPSS rescore
  31. 2026-06-11 22:17 UTCVendor advisory
  32. 2026-06-11 14:00 UTCEPSS rescore
  33. 2026-06-10 22:19 UTCEPSS rescore
  34. 2026-06-10 14:57 UTCVendor advisory
  35. 2026-06-10 13:22 UTCEPSS rescore
  36. 2026-06-10 02:51 UTCVendor advisory
  37. 2026-06-09 14:45 UTCVendor advisory
  38. 2026-06-08 14:17 UTCEPSS rescore
  39. 2026-06-08 14:17 UTCEPSS rescore
  40. 2026-06-08 11:46 UTCVendor advisory
  41. 2026-06-07 23:18 UTCVendor advisory
  42. 2026-06-07 15:25 UTCEPSS rescore
  43. 2026-06-07 15:25 UTCEPSS rescore
  44. 2026-06-07 11:09 UTCVendor advisory
  45. 2026-06-06 13:47 UTCEPSS rescore
  46. 2026-06-06 13:47 UTCEPSS rescore
  47. 2026-06-05 22:47 UTCEPSS rescore
  48. 2026-06-05 06:10 UTCEPSS rescore
  49. 2026-06-05 06:10 UTCEPSS rescore
  50. 2026-06-04 13:12 UTCEPSS rescore
  51. 2026-06-04 13:12 UTCEPSS rescore
  52. 2026-06-02 20:13 UTCEPSS rescore
  53. 2026-06-01 13:52 UTCEPSS rescore
  54. 2026-06-01 13:52 UTCEPSS rescore
  55. 2026-05-31 22:30 UTCEPSS rescore
  56. 2026-05-31 22:30 UTCEPSS rescore
  57. 2026-05-31 00:16 UTCEPSS rescore
  58. 2026-05-31 00:16 UTCEPSS rescore
  59. 2026-05-29 13:44 UTCEPSS rescore
  60. 2026-05-29 13:44 UTCEPSS rescore
  61. 2026-05-28 13:44 UTCEPSS rescore
  62. 2026-05-28 13:44 UTCEPSS rescore
  63. 2026-05-27 13:40 UTCEPSS rescore
  64. 2026-05-27 13:40 UTCEPSS rescore
  65. 2026-05-26 13:44 UTCEPSS rescore
  66. 2026-05-26 07:18 UTCEPSS rescore
  67. 2026-05-21 22:43 UTCEPSS rescore
  68. 2026-05-20 22:38 UTCEPSS rescore
  69. 2026-05-20 19:29 UTCEG score recompute
  70. 2026-05-20 19:29 UTCVendor advisory
  71. 2026-05-20 11:22 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-4634?
CVE-2026-4634 is a high vulnerability published on April 2, 2026. A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times,…
When was CVE-2026-4634 disclosed?
CVE-2026-4634 was first published in the National Vulnerability Database on April 2, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4634 actively exploited?
CVE-2026-4634 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 41.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-4634?
CVE-2026-4634 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-4634?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4634, 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.

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