# CVE-2026-116479: a2aproject a2a-java information exposure in JSON-RPC error handler

Source: https://junglewise.ai/threats/cve-2026-116479-a-flaw-has-been-found-in-a2aproject-a2a-java-up-to-1-2-0-final  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-26. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

CVE-2026-116479 · Severity: medium · CVSS 4.3 · Published 2026-10-26

The a2a-java library is a Java SDK for the Agent2Agent protocol. A flaw in the JSON-RPC error handler's getMessage function allows sensitive information to be exposed through error messages returned to remote clients. An attacker can trigger errors to retrieve internal system details that could aid further attacks.

Technologies: [A2aproject A2a-Java](https://junglewise.ai/threats/technologies/a2a-java). Vendors: [A2aproject](https://junglewise.ai/threats/vendors/a2aproject).

## Quick answers

**Is CVE-2026-116479 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116479 being exploited in the wild.

**How severe is CVE-2026-116479?** Medium severity, with a CVSS score of 4.3, published 26 October 2026.

**Which products and versions are affected?** A2aproject A2a-Java up to 1.2.0.Final.

**Is there a fix for CVE-2026-116479?** Yes: fixed in 1.3.0.Final. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116479 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-116479?** Check whether you run A2aproject A2a-Java at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.3.0.Final

## Technical details

The vulnerability is an information disclosure (CWE-209) in the JSON-RPC error handler component where raw exception messages containing internal system details are returned to clients without sanitization. This can be triggered remotely by any client capable of sending JSON-RPC requests. The fix sanitizes error messages to return generic "Internal error" strings while logging original exceptions server-side for observability.

## Affected products

- a2aproject a2a-java up to 1.2.0.Final

## Timeline

- 2026-10-26: disclosed
- 2026-08-12: patched

## References

- [https://github.com/a2aproject/a2a-java/](https://github.com/a2aproject/a2a-java/)
- [https://github.com/a2aproject/a2a-java/commit/bbee3369f3825d0fba2373d821f6dc6d4fc82ec0](https://github.com/a2aproject/a2a-java/commit/bbee3369f3825d0fba2373d821f6dc6d4fc82ec0)

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