CVE-2026-111764

A2A Java SDK has a fail-open default task authorization

Published Oct 20, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-qw47-mcm5-934w A2A Java SDK has a fail-open default task authorization
History
Type Values Removed Values Added
First Time appeared A2aproject
A2aproject a2a-java
Vendors & Products A2aproject
A2aproject a2a-java
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title A2A Java SDK has a fail-open default task authorization
Weaknesses CWE-1188
CWE-862
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 20, 2026, 4:15 PM
Reserved
Oct 16, 2026, 5:52 PM
Status
Awaiting Analysis
Published
Oct 20, 2026, 4:17 PM
Modified
Oct 20, 2026, 7:56 PM