Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters
CVSS score
7.5
EPSS probability
%0.9
Risk score
0.1
Published
6 mo ago
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Impact on My Inventory
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-4634 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
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.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-4634 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | Red Hat | Red Hat build of Keycloak 26.2 | View |
| 2 | Red Hat | Red Hat build of Keycloak 26.2 | View |
| 3 | Red Hat | Red Hat build of Keycloak 26.2.15 | View |
| 4 | Red Hat | Red Hat build of Keycloak 26.4 | View |
| 5 | Red Hat | Red Hat build of Keycloak 26.4 | View |
| 6 | Red Hat | Red Hat build of Keycloak 26.4.11 | View |
| 7 | Red Hat | Red Hat Single Sign-On 7.6.13 | View |
| 8 | Red Hat | Red Hat Single Sign-On 7.6 for RHEL 7 | View |
| 9 | Red Hat | Red Hat Single Sign-On 7.6 for RHEL 8 | View |
| 10 | Red Hat | Red Hat Single Sign-On 7.6 for RHEL 9 | View |
| 11 | Red Hat | RHEL-8 based Middleware Containers | View |
| 12 | redhat | build of keycloak | View |
| 13 | redhat | build of keycloak | View |
| 14 | redhat | build of keycloak | View |
| 15 | redhat | build of keycloak | View |
| 16 | redhat | build of keycloak | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 7.5 | CVSS V31 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD |
| 7.5 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CVE CNA |
| 7.5 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CVE ADP |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-4634 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-4634 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
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