CVE-2026-111763 | BDVDB-2026-393103 Detail
a2aprojecta2a-java
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.
Impact#
Per CVSS v4.0: confidentiality impact high, integrity impact none, availability impact none. Attack vector: local.
Weaknesses#
- CWE-522 Insufficiently Protected Credentials
References#
- https://github.com/a2aproject/a2a-java/security/advisories/GHSA-9rhm-2h4x-jwmx
- https://github.com/a2aproject/a2a-java/security/advisories/GHSA-4fpj-g9jf-9rgg
- https://github.com/a2aproject/a2a-java/pull/1097
- https://github.com/a2aproject/a2a-java/commit/2a36530d75e11bcf9b81f543464dbe193ca6478e
- https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.