CVE-2026-111761
MediumCVSS 5.8Summary
A2A Java SDK before 1.3.0.Final has a vulnerability in BasePushNotificationSender that sends task data to a URL without destination validation, scheme restrictions, or redirect limits. An unauthenticated attacker can register an arbitrary destination, causing the server to send requests to internal or local resources.
Risk Assessment
An attacker could use the server to scan or attack internal services, including cloud metadata, potentially leading to information disclosure or further attacks.
Recommendation
Update A2A Java SDK to version 1.3.0.Final or later.
Other vulnerabilities in A2A Java SDK
See all- CVE-2026-111765High
A2A Java SDK from 1.3.0.Final before 1.3.2.Final: the AndroidA2AHttpClient synchronous POST path overrides the disabled-redirect setting with PostBuilder's followRedirects=true. JSONRPCTransport and RestTransport add interceptor-produced authentication headers and call synchronous post() without disabling redirects, disclosing a configured API key or token to another authority on redirect.
- CVE-2026-111764High
A2A Java SDK prior to 1.3.0.Final: the default InMemoryTaskStore configuration performs no authorization on task reads. The no-argument constructor sets authorizationProvider to null, and get(String taskId) returns the stored task without checking caller or owner. In a multi-caller deployment, a caller who knows another caller's task ID can retrieve task status, context ID, message history, and artifacts; default transport endpoints do not enforce authentication.
- CVE-2026-111763Medium
A2A Java SDK prior to 1.3.0.Final allows a malicious or compromised remote agent to cause the default JDK-based client to forward a configured API key to a third-party server. AuthInterceptor uses APIKeySecurityScheme.name() from the remote AgentCard as the HTTP header name without checking that the declared location is HEADER, and JdkA2AHttpClient uses followRedirects(NORMAL), so an agent-controlled cross-origin redirect forwards the credential-bearing header.
- CVE-2026-111762Medium
A2A Java SDK before 1.3.0.Final has a vulnerability in RestHandler.parseRequestBody that logs the entire JSON request body at SEVERE level when protobuf parsing fails. With push notifications enabled, this can expose tokens and authentication credentials in server logs.
Original NVD description (English source)
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, BasePushNotificationSender in server-common sends task data to the URL in TaskPushNotificationConfig without destination validation, scheme restrictions, or bounds on redirects. InMemoryPushNotificationConfigStore.setInfo stores the URL verbatim, and onCreateTaskPushNotificationConfig does not validate the destination. In the default deployment with push notifications enabled, an unauthenticated caller can register a destination through an inline SendMessage configuration or CreateTaskPushNotificationConfig for an existing task, causing task status and artifact updates to send requests from the server's network position to loopback, private, link-local cloud-metadata, IPv6 unique-local, unspecified, or multicast destinations where routing permits. JdkA2AHttpClient and VertxA2AHttpClient follow redirects, allowing a webhook redirect to bypass creation-time destination checks and convert a POST into a GET; hostname-only checks also do not prevent DNS rebinding. Direct POST delivery can push attacker-influenced task data into internal services, whereas a redirected POST-to-GET request drops the body. The sender discards the fetched response and does not expose delivery success or failure, so the demonstrated behavior does not provide response read-back. No credentials or user interaction are required. This issue is fixed in version 1.3.0.Final.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS