Bug 2540080 (CVE-2026-97367)

Summary:	CVE-2026-97367 keycloak-services: keycloak-services: DCR azp and sid claim substitution allows Account REST session takeover
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	aschwart, aszczucz, boliveir, drichtar, mposolda, pjindal, rmartinc, security-response-team, ssilvert, sthorger, vmuzikar
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:	A flaw was found in the Keycloak Account REST API where it incorrectly handles session identification. A malicious client owner can manipulate their own security tokens to point to a different user's active session. This allows the attacker to access and modify the victim's account information, potentially leading to a full account takeover by changing the recovery email and resetting the password.	Story Points:	---
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Last Closed:		Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Deadline:	2026-11-23

Description OSIDB Bzimport 2026-09-24 14:00:21 UTC

A flaw was found in Keycloak's Account REST API session binding mechanism. The issue exists because the sid session ID claim is not included in the blocked claim list for Dynamic Client Registration DCR protocol mappers. A malicious DCR client owner can configure mappers to substitute the azp authorized party and sid claims in their access token with values derived from user-controlled profile fields. When the Account REST API processes this manipulated token, the identity token verification resolves the user session based on the provided sid without verifying that the subject sub claim in the token matches the user associated with that session. Consequently, the API returns the victim's session data. An attacker with low privileges can exploit this to read and write a victim's account profile, change the recovery email, and perform a full account takeover via password reset.