Is CVE-2026-116477 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-116477 being exploited in the wild.

How severe is CVE-2026-116477?

Medium severity, with a CVSS score of 4.3, published 26 October 2026.

Which products and versions are affected?

A2aproject A2a-Dotnet up to 1.0.0-preview2.

Is there a fix for CVE-2026-116477?

Yes: fixed in 1.0.0-preview3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-116477 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-116477?

Check whether you run A2aproject A2a-Dotnet 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.

CVE-2026-116477: a2aproject a2a-dotnet information exposure in JSON-RPC error messages

CVE-2026-116477 · Severity: medium · CVSS 4.3 · Published 2026-10-26

a2a-dotnet is a C#/.NET SDK for the A2A protocol. A flaw in the JSON-RPC request processor allows attackers to remotely trigger detailed error messages that expose internal system details, potentially aiding further attacks. Upgrading to version 1.0.0-preview3 resolves the issue.

Vendors: A2aproject.

Quick answers

Is CVE-2026-116477 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-116477 being exploited in the wild.
How severe is CVE-2026-116477?: Medium severity, with a CVSS score of 4.3, published 26 October 2026.
Which products and versions are affected?: A2aproject A2a-Dotnet up to 1.0.0-preview2.
Is there a fix for CVE-2026-116477?: Yes: fixed in 1.0.0-preview3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-116477 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-116477?: Check whether you run A2aproject A2a-Dotnet 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: 1.0.0-preview3

Technical details

The A2AJsonRpcProcessor.ProcessRequestAsync method in the parser component fails to sanitize error messages returned during JSON-RPC request handling. An unauthenticated remote attacker can craft malformed requests to trigger parsing errors that leak internal implementation details. The fix in commit ccbd12b sanitizes error messages to prevent this information disclosure.

Affected products

a2aproject a2a-dotnet up to 1.0.0-preview2

Timeline

2026-10-26: disclosed

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.