Access token disclosure via forged client data
Published May 19, 2026 · Updated May 19, 2026
Security control bypass in Red Hat build of Keycloak 26.4 before 26.4.12 allows remote authenticated users to obtain access tokens. During an OIDC session restart, the server accepts forged client data as immutable and issues a token even when implicit flow is disabled. Exploitation requires low-privilege credentials and the client ID; this flow exposes tokens through server logs, proxy logs, and HTTP Referrer headers.
Summary
What happened
Security control bypass in Red Hat build of Keycloak 26.4 before 26.4.12 allows remote authenticated users to obtain access tokens. During an OIDC session restart, the server accepts forged client data as immutable and issues a token even when implicit flow is disabled. Exploitation requires low-privilege credentials and the client ID; this flow exposes tokens through server logs, proxy logs, and HTTP Referrer headers.
The record
- CVE
- CVE-2026-7571
- Published
- May 19, 2026
- Updated
- May 19, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat build of Keycloak
- Classifications
- CWE-472, T1528
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- May 19, 2026CVE publishedPublication date reported by the CVE source.
- May 19, 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 is affected?
Published CVSS scores
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Attacks
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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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