CVE-2026-0707: Keycloak Authorization Header Parsing Flaw
Summary
CVE-2026-0707: Keycloak has Incorrect Behavior Order: Authorization Before Parsing and Canonicalization. Affects org.keycloak:keycloak-parent versions < 26.5.0. No fix is published. How to fix ↓
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Background
Keycloak is an open-source identity and access management solution that enables secure authentication and authorization for applications and services. It provides features such as single sign-on (SSO), user federation, and identity brokering. However, a flaw in its Authorization header parser has been identified, which could lead to security issues if not addressed.
Vulnerability Detail
A flaw was found in Keycloak where the Authorization header parser is overly permissive regarding the formatting of the 'Bearer' authentication scheme. It accepts non-standard characters, such as tabs, as separators and tolerates case variations that deviate from RFC 6750 specifications. This could potentially allow unauthorized access or manipulation of authentication tokens, leading to security vulnerabilities in applications relying on Keycloak for authentication.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, ensure that your application validates the Authorization header format strictly before processing it. This can help mitigate the risk of unauthorized access until the package is updated.
Conclusion
The vulnerability CVE-2026-0707 in Keycloak poses a significant risk due to its flawed Authorization header parser. It is crucial to update to the patched version to mitigate potential security threats. Additionally, using tools like Vulert can help monitor and manage vulnerabilities effectively.
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FAQ
CVE-2026-0707 is a vulnerability in Keycloak that involves an overly permissive Authorization header parser, which could lead to security issues.
The risks include unauthorized access to applications and services that rely on Keycloak for authentication, potentially leading to data breaches.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
Update your Keycloak package to version 26.5.1 or later to patch the vulnerability and ensure strict validation of the Authorization header format.
Vulert is a tool that monitors and alerts for open-source vulnerabilities in your software using just the pom.xml file, providing real-time insights.
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