CVE-2026-15571

Keycloak-services: keycloak-services: predictable account-linking hash enables account takeover via malicious oidc client

Published Aug 18, 2026 CVSS 3.1 · 7.3 High EPSS < 1% KEV · Not listed
Description
A flaw was found in the legacy client-initiated account-linking endpoint of Keycloak, a widely used open-source identity and access management solution. The mechanism used to protect the account-linking process from unauthorized requests relies on a hash that can be predicted by a malicious OIDC client. By tricking a user into authenticating, an attacker-controlled client can forge a valid linking URL to connect the victim's account to an attacker's external identity. This results in a full account takeover, allowing the attacker to log in as the victim.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Redhat data Grid 8
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign On
Vendors & Products Redhat build Of Keycloak
Redhat data Grid 8
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign On
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak:26.6::el9
References
Type Values Removed Values Added
Description A flaw was found in the legacy client-initiated account-linking endpoint of Keycloak, a widely used open-source identity and access management solution. The mechanism used to protect the account-linking process from unauthorized requests relies on a hash that can be predicted by a malicious OIDC client. By tricking a user into authenticating, an attacker-controlled client can forge a valid linking URL to connect the victim's account to an attacker's external identity. This results in a full account takeover, allowing the attacker to log in as the victim.
Title Keycloak-services: keycloak-services: predictable account-linking hash enables account takeover via malicious oidc client
First Time appeared Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
Weaknesses CWE-341
CPEs cpe:/a:redhat:build_keycloak:26.6
cpe:/a:redhat:jboss_data_grid:8
cpe:/a:redhat:jbosseapxp
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Aug 20, 2026, 2:07 PM
Reserved
Jul 13, 2026, 7:12 AM
Status
Awaiting Analysis
Published
Aug 18, 2026, 9:16 PM
Modified
Aug 20, 2026, 3:17 PM
Severity
Important
Public date
Aug 18, 2026, 7:41 PM