CVE-2026-111763

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.

CVSS

No CVSS.

References

Link	Resource
https://github.com/a2aproject/a2a-java/commit/2a36530d75e11bcf9b81f543464dbe193ca6478e
https://github.com/a2aproject/a2a-java/pull/1097
https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final
https://github.com/a2aproject/a2a-java/security/advisories/GHSA-4fpj-g9jf-9rgg
https://github.com/a2aproject/a2a-java/security/advisories/GHSA-9rhm-2h4x-jwmx

Configurations

No configuration.

History

20 Oct 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-20 16:17

Updated : 2026-10-21 16:17

NVD link : CVE-2026-111763

Mitre link : CVE-2026-111763

CVE.ORG link : CVE-2026-111763

JSON object : View

Products Affected

No product.

CWE

CWE-522

Insufficiently Protected Credentials

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