Red Hat Keycloak/Single Sign-On 7 JWT Token allocation of resources

Summaryinfo

A vulnerability categorized as problematic has been discovered in Red Hat Keycloak and Single Sign-On 7. This affects an unknown function of the component JWT Token Handler. Such manipulation leads to allocation of resources. This vulnerability is uniquely identified as CVE-2025-2559. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Red Hat Keycloak and Single Sign-On 7 (affected version unknown). Affected by this issue is an unknown functionality of the component JWT Token Handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

A flaw was found in Keycloak. When the configuration uses JWT tokens for authentication, the tokens are cached until expiration. If a client uses JWT tokens with an excessively long expiration time, for example, 24 or 48 hours, the cache can grow indefinitely, leading to an OutOfMemoryError. This issue could result in a denial of service condition, preventing legitimate users from accessing the system.

The advisory is shared for download at access.redhat.com. This vulnerability is handled as CVE-2025-2559 since 03/20/2025. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 06/04/2025). The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-8064). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• Red Hat

Name

• Keycloak
• Single Sign-On 7

License

• open-source

Website

• Vendor: https://www.redhat.com/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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