CVE-2026-111763 A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect
- Exploited in the wild
- Not known
- Fix
- Available
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
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 | 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.
Sources
Also known as GHSA-9rhm-2h4x-jwmx.