A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect

{
  "id": "fdd824aa7302cea558a5d799ec1563b51980cbde2b7ae32856c3b78c9029d269",
  "url": "https://osv.dev/vulnerability/GHSA-9rhm-2h4x-jwmx",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect",
    "summary": "*Impact.** A malicious or compromised A2A agent can cause the client's API key credential to be forwarded to an arbitrary third-party server. The agent serves an AgentCard with an `APIKeySecurityScheme` specifying a custom header name, then responds with an HTTP redirect. The JDK HttpClient follows the redirect and forwards the custom header containing the credential, since only the standard `Authorization` header may be stripped on cross-origin redirects. **Where.** `client/transport/spi/src/main/java/org/a2aproject/sdk/client/transport/spi/interceptors/auth/AuthInterceptor.java:69` in `intercept` **What.** The `apiKeySecurityScheme.name()` field from the remote agent's AgentCard (untrusted, server-controlled data) is used directly as the HTTP header name when placing client credentials. Combined with `JdkA2AHttpClient`'s `followRedirects(NORMAL)` policy, credentials under custom header names survive cross-origin redirects (only `Authorization` is stripped on newer JDKs), allowing a malicious agent to leak client credentials to third-party servers. Additionally, `AuthInterceptor` does not check that `location==HEADER` before placing the credential as a header. **Exploit scenario.** Client configures an API key credential for agent's security scheme `myAuth`. The malicious agent returns an AgentCard where `securitySchemes` includes `myAuth` as `APIKeySecurityScheme` with `name='X-Leaked-Cred'` and `location=HEADER`. `AuthInterceptor` places the credential in the `X-Leaked-Cre",
    "evidence": "osv:GHSA-9rhm-2h4x-jwmx",
    "products": [
      {
        "name": {
          "value": "org.a2aproject.sdk:a2a-java-sdk-parent",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.3.0.Final",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.0.0.Alpha4",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.0.0.Beta1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.0.0.CR1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.0.0.Final",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.1.0.Final",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.2.0.Final",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "GHSA-9rhm-2h4x-jwmx",
      "aliases": [
        "CVE-2026-111763",
        "GHSA-9rhm-2h4x-jwmx"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.3.0.Final"
                }
              ]
            }
          ],
          "package": {
            "name": "org.a2aproject.sdk:a2a-java-sdk-parent",
            "purl": "pkg:maven/org.a2aproject.sdk/a2a-java-sdk-parent",
            "ecosystem": "Maven"
          },
          "versions": [
            "1.0.0.Alpha4",
            "1.0.0.Beta1",
            "1.0.0.CR1",
            "1.0.0.Final",
            "1.1.0.Final",
            "1.2.0.Final"
          ],
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-9rhm-2h4x-jwmx/GHSA-9rhm-2h4x-jwmx.json"
          }
        }
      ],
      "modified": "2026-10-21T03:11:56.125202083Z",
      "provider": "osv",
      "references": [
        "https://github.com/a2aproject/a2a-java/security/advisories/GHSA-4fpj-g9jf-9rgg",
        "https://github.com/a2aproject/a2a-java/security/advisories/GHSA-9rhm-2h4x-jwmx",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-111763",
        "https://github.com/a2aproject/a2a-java/pull/1097",
        "https://github.com/a2aproject/a2a-java/commit/2a36530d75e11bcf9b81f543464dbe193ca6478e",
        "https://github.com/a2aproject/a2a-java",
        "https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-522"
        ],
        "severity": "MODERATE",
        "github_reviewed": true,
        "nvd_published_at": "2026-10-20T16:17:00Z",
        "github_reviewed_at": "2026-10-20T21:04:16Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-111763",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 391579,
  "published_at": "2026-10-20T21:04:16+00:00"
}