a2aproject a2a-java up to 1.2.x InMemoryTaskStore InMemoryTaskStore.get taskId improper authorization

Summaryinfo

A vulnerability described as problematic has been identified in a2aproject a2a-java up to 1.2.x. Affected by this vulnerability is the function InMemoryTaskStore.get of the component InMemoryTaskStore. Such manipulation of the argument taskId leads to improper authorization. This vulnerability is referenced as CVE-2026-111764. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in a2aproject a2a-java up to 1.2.x. Affected by this issue is the function InMemoryTaskStore.get of the component InMemoryTaskStore. The manipulation of the argument taskId with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality. CVE summarizes:

A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, the default InMemoryTaskStore configuration performs no authorization on task reads: the no-argument constructor sets authorizationProvider to null, and InMemoryTaskStore.get(String taskId) returns the stored task without checking the caller or owner. Authorization depends on supplying a TaskAuthorizationProvider and routing requests through AuthorizationRequestHandlerDecorator, whether installed through CDI or explicitly by the application. Default store wiring and manually constructed DefaultRequestHandler.builder().build() handlers, including integrations such as Spring, leave task reads unprotected when no effective authorization-provider and decorator check is installed. In a multi-caller deployment using the default configuration, a caller who knows or guesses another caller's task ID can retrieve the task status, context ID, message history, and artifacts. The default/reference transport endpoints do not enforce authentication, so the task-read disclosure is reachable by an unauthenticated caller rather than requiring a privileged account. This issue is fixed in version 1.3.0.Final.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-111764 since 10/16/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 1.3.0.Final eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• a2aproject

Name

• a2a-java

Version

• 1.0
• 1.1
• 1.2

Website

• Product: https://github.com/a2aproject/a2a-java/

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