Bug 2433783 (CVE-2026-1529)

Summary: CVE-2026-1529 org.keycloak.services.resources.organizations: Keycloak: Unauthorized organization registration via improper invitation token validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: aschwart, boliveir, mposolda, pjindal, rmartinc, security-response-team, ssilvert, sthorger, vmuzikar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in Keycloak. An attacker can exploit this vulnerability by modifying the organization ID and target email within a legitimate invitation token's JSON Web Token (JWT) payload. This lack of cryptographic signature verification allows the attacker to successfully self-register into an unauthorized organization, leading to unauthorized access.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Deadline: 2026-03-31   

Description OSIDB Bzimport 2026-01-28 12:31:20 UTC
Organization invitation tokens in Keycloak are parsed without cryptographic signature verification during the registration flow. This allows an attacker to take a legitimate invitation, modify the organization ID (org_id) and the target email (eml) within the JWT payload, and successfully self-register into an unauthorized organization.