CVE-2026-111763

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-10-16 17:52 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-10-20 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-10-21 16:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.1% in the next 30 days (EPSS).
• Severity: 5.7 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-10-20 16:17 UTC

Last modified

2026-10-21 16:17 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-522

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 5.7

Attack vector

Local

Complexity

Low

Attack requirements

Present

Privileges needed

Low

User interaction

None

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-111763.md and follow it. Check whether this project is affected by CVE-2026-111763. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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