{"cve":"CVE-2026-111763","nvd":{"published":"2026-10-20T16:17:00.550","modified":"2026-10-21T16:17:14.520","status":"Awaiting Analysis","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.","cvss_v4":{"vector":"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","score":5.7},"cvss_v3":null,"cwes":["CWE-522"],"references":["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"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-111763","score":0.00141,"percentile":0.03375,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-9rhm-2h4x-jwmx","url":"https://osv.dev/vulnerability/GHSA-9rhm-2h4x-jwmx","summary":"A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect","modified":"2026-10-21T03:11:56.125202083Z","packages":[{"ecosystem":"Maven","name":"org.a2aproject.sdk:a2a-java-sdk-parent","purl":"pkg:maven/org.a2aproject.sdk/a2a-java-sdk-parent","ranges":["<1.3.0.Final"],"fixed":["1.3.0.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}