Java SDK flaw exposes task data; verify 1.3.0.Final release status

The A2A Java SDK package `org.a2aproject.sdk:a2a-java-sdk-server-common` contains a high-severity vulnerability identified as CVE-2026-111764. According to the GitHub advisory GHSA-qw47-mcm5-934w, versions up to 1.2.0.Final are vulnerable. The advisory lists 1.3.0.Final as the patched version, but notes this is a placeholder pending release. Managed service providers must verify the actual availability of a secure update before deploying changes.

How it unfolded

• Researchers identified that the default `InMemoryTaskStore` sets the authorization provider to null.
• The `get` method performs a bare map lookup without checking caller identity or ownership.
• The advisory notes that authorization is only enforced when specific CDI routing is used.
• The default configuration remains unsafe, exposing task data to any caller with the task ID.

Who is affected

Any system using the `org.a2aproject.sdk:a2a-java-sdk-server-common` package in versions less than 1.3.0.Final is affected. This includes applications using the default task store, those manually building the `DefaultRequestHandler`, or integrations using non-CDI stacks like Spring. In these environments, the authorization checks are bypassed. Attackers can retrieve task status, context, message history, and artifacts by guessing or knowing the task ID.

Our take on the response

The vulnerability stems from insecure default initialization, classified as CWE-1188, combined with missing authorization, classified as CWE-862. The CVSS v3.1 score is 7.5, rating the severity as High. The flaw allows network-accessible, low-complexity exploitation without user interaction. Because the safe posture requires opt-in configuration, default deployments are exposed. Teams should assume their instances are vulnerable if they rely on default SDK settings.

Who needs to act first

Teams should prioritize systems exposing task data to external users or untrusted internal services. Check whether applications use the default task store configuration. If the patched version is confirmed available, test the update in a non-production environment before rolling it out. Ensure backups of current configurations exist before applying changes. Monitor logs for unauthorized access attempts to task resources. Reduce exposure by restricting network access to endpoints handling task data until a fix is verified.

What to do and how to stay safe: CVE-2026-111764

• Verify if your environment uses the default A2A Java SDK task store configuration.
• Check if a confirmed, non-placeholder patch version has been released by the vendor.
• Implement network-level restrictions to limit access to task data endpoints.
• Monitor authentication logs for requests accessing task IDs belonging to other users.

Step-by-step guide: Vulnerability Prioritization: How to Rank Risks Without Wasting Time

General security guidance from the Patch Observer newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

Is CVE-2026-111764 currently being exploited in the wild?

The source material does not state whether the vulnerability is being actively exploited in the wild.

Which specific versions of the A2A Java SDK are vulnerable?

Versions less than 1.3.0.Final, including 1.2.0.Final, are vulnerable according to the advisory.

What data can an attacker access through this vulnerability?

Attackers can access task status, context, message history, and artifacts created by other callers.