Stored XSS via case-insensitive redirect URI validation
Published Jun 25, 2026 · Updated Jun 25, 2026
Stored XSS in Red Hat build of Keycloak 26.4 before 26.4.13 and 26.6 before 26.6.4 allows remote authenticated users to run script. Client URI validation compares disallowed javascript: and data: schemes case-sensitively, so mixed-case schemes survive registration and execute in the Keycloak origin when followed. Exploitation requires manage-client permission or client-registration access plus a victim click, enabling access to data and actions available in that origin.
Summary
What happened
Stored XSS in Red Hat build of Keycloak 26.4 before 26.4.13 and 26.6 before 26.6.4 allows remote authenticated users to run script. Client URI validation compares disallowed javascript: and data: schemes case-sensitively, so mixed-case schemes survive registration and execute in the Keycloak origin when followed. Exploitation requires manage-client permission or client-registration access plus a victim click, enabling access to data and actions available in that origin.
The record
- CVE
- CVE-2026-9086
- Published
- Jun 25, 2026
- Updated
- Jun 25, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat build of Keycloak
- Classifications
- CWE-79, T1059.007
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 25, 2026CVE publishedPublication date reported by the CVE source.
- Jun 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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