# CVE-2026-111764: A2A Java SDK has a fail-open default task authorization


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 20 Oct 2026
- **Updated:** 20 Oct 2026
- **Also known as:** GHSA-qw47-mcm5-934w

## What is CVE-2026-111764?

CVE-2026-111764 is a high-severity vulnerability in a2aproject a2a-java, published on 20 Oct 2026. 

### Official 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.

Weakness: CWE-862 (Missing Authorization), CWE-1188 (Initialization of a Resource with an Insecure Default)

## Which versions are affected by CVE-2026-111764?

2 open source packages ship an affected version, including org.a2aproject.sdk:a2a-java-sdk-server-common.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.a2aproject.sdk:a2a-java-sdk-server-common` | Maven | All versions | 1.3.0.Final |
| `org.a2aproject.sdk:a2a-java-sdk-server-common` | Maven | All versions | 1.3.0.Final |

## How do I fix CVE-2026-111764?

Upgrade org.a2aproject.sdk:a2a-java-sdk-server-common to 1.3.0.Final or later.

## Is CVE-2026-111764 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111764 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111764 and fix it if it is affected.

What it is: CVE-2026-111764 is a high-severity vulnerability in a2aproject a2a-java, published on 20 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111764 exists.

Affected packages and fixed versions:
- org.a2aproject.sdk:a2a-java-sdk-server-common (Maven): affected all versions; fixed in 1.3.0.Final
- org.a2aproject.sdk:a2a-java-sdk-server-common (Maven): affected all versions; fixed in 1.3.0.Final

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-111764/ (Markdown: https://insights.sbomify.com/CVE-2026-111764/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111764
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111764
- OSV: https://osv.dev/vulnerability/CVE-2026-111764

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111764/
Summaries are generated and may contain mistakes; the official description above is the record.