CVE-2026-4634

highpriority · track · 0EPSS 0.009 · 58 %ileDEEUJPRUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.86% (58th) EPSS

CVSS 7.5 · high

Is it mine?

26 products

Check your exposure

Who says so?

7 sources

cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-23

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

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · secalert@redhat.com USexploitability 3.9 · impact 3.6

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondaryexploitability 3.9 · impact 3.6

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · OSV

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-1050USCWE-1050USCWE-1050US

affected products (26)

Products and version ranges known to be affected.

Open Source Keycloak <26.5.7all versionscert_bundDE
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
Open Source Keycloak< 26.5.7cert_bundDE
Red Hat Red Hat build of Keycloak 26.2< 26.2-18enisa_euvdEU
Red Hat Red Hat build of Keycloak 26.2< 26.2.15-1enisa_euvdEU
Red Hat Red Hat build of Keycloak 26.4< 26.4-14enisa_euvdEU
Red Hat Red Hat build of Keycloak 26.4< 26.4.11-1enisa_euvdEU
Red Hat, Inc. RHEL-8 based Middleware Containersall versionsfstec_bduRU
Red Hat, Inc. Red Hat Build of Keycloak≤ 26.4fstec_bduRU
Red Hat, Inc. Red Hat Build of Keycloak≤ 26.2.15fstec_bduRU
Red Hat, Inc. Red Hat Build of Keycloak≤ 26.4.11fstec_bduRU
Red Hat, Inc. Red Hat Single Sign-On≤ 7.6 for RHEL 9fstec_bduRU
Red Hat, Inc. Red Hat Single Sign-On≤ 7.6 for RHEL 7fstec_bduRU
Red Hat, Inc. Red Hat Single Sign-On≤ 7.6.13fstec_bduRU
Red Hat, Inc. Red Hat Single Sign-On≤ 7.6 for RHEL 8fstec_bduRU
АО «СберТех» Platform V IAM SE≤ 2.3.1fstec_bduRU
redhat build of keycloakall versionsnvdUScpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*
redhat build of keycloak= 26.2nvdUScpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*
redhat build of keycloak= 26.2.15nvdUScpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*
redhat build of keycloak= 26.4nvdUScpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*

showing 20 of 26

advisories (4)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-0977Keycloak: Mehrere SchwachstellenDeutsch2026-04-06csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Keycloak ausnutzen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Daten zu manipulieren, und um Sicherheitsvorkehrungen zu umgehen.
GHSA-h4wv-g838-66g3Keycloak: Application-Level DoS via Scope Processing2026-04-02ghsa · osvUS
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.
BIT-keycloak-2026-4634Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters2026-08-25vendor · osvUS
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.
JVNDB-2026-026852JVN iPedia advisory JVNDB-2026-0268522026-08-05vendor · jvndbJP

also known as (6)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu osv cert_bund nvd jvndb NVD CVE.org MITRE

published 2026-04-02modified 2026-10-14

references (20)

External citations — patches, advisories, analysis.

scry

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