# CVE-2026-111763: A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect


- **Severity:** Medium 5.7 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 20 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-9rhm-2h4x-jwmx

## What is CVE-2026-111763?

CVE-2026-111763 is a medium-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, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials through `CredentialService`, `AuthInterceptor.intercept` in `client/transport/spi/src/main/java/org/a2aproject/sdk/client/transport/spi/interceptors/auth/AuthInterceptor.java` uses `APIKeySecurityScheme.name()` from the remote AgentCard directly as the HTTP header name containing the credential, without checking that the declared location is HEADER. JdkA2AHttpClient uses followRedirects(NORMAL), so an agent-controlled cross-origin redirect forwards the custom credential-bearing header even when the standard Authorization header is stripped. The attack requires configured API key credentials for the agent's security scheme and control of the agent's AgentCard and redirect response, but no additional client privileges. This issue is fixed in version 1.3.0.Final.

Weakness: CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2026-111763?

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


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

## How do I fix CVE-2026-111763?

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

## Is CVE-2026-111763 being exploited?

There is no known exploitation of CVE-2026-111763 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111763 and fix it if it is affected.

What it is: CVE-2026-111763 is a medium-severity vulnerability in a2aproject a2a-java, published on 20 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-111763 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.a2aproject.sdk:a2a-java-sdk-parent (Maven): affected all versions; fixed in 1.3.0.Final
- org.a2aproject.sdk:a2a-java-sdk-parent (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-2026-111763/ (Markdown: https://insights.sbomify.com/CVE-2026-111763/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111763
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111763
- OSV: https://osv.dev/vulnerability/CVE-2026-111763

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111763/
Summaries are generated and may contain mistakes; the official description above is the record.