CVE-2026-116477 a2aproject CVE debrief

Who should care

Defenders responsible for systems using a2aproject a2a-dotnet up to 1.0.0-preview2 should assess exposure and prioritize upgrading to version 1.0.0-preview3 or later. This involves reviewing the current deployment, identifying potential vulnerabilities, and applying the necessary patches or mitigations. Additionally, defenders should review compensating controls for exposed systems while remediation is scheduled and verified.

Why it matters

CVE-2026-116477 is a security vulnerability in a2aproject a2a-dotnet up to 1.0.0-preview2 that leads to information exposure through error messages and can be exploited remotely. Defenders should prioritize upgrading to version 1.0.0-preview3 or later.

• Information exposure through error messages
• Remote exploitation possible, requires verification
• Upgrade to version 1.0.0-preview3 or later for resolution

Technical summary

The A2AJsonRpcProcessor.ProcessRequestAsync function in the src/A2A.AspNetCore/A2AJsonRpcProcessor.cs file of the a2aproject a2a-dotnet up to 1.0.0-preview2 is vulnerable to information exposure through error messages. The vulnerability can be exploited remotely. Defenders should prioritize upgrading to version 1.0.0-preview3 or later to resolve this issue. The patch identifier is ccbd12b6108a6a8f0fd5d8b4a9ece3c8a94ba1e4. Affected product deployments should be reviewed for exposure, and necessary mitigations should be applied.

Defensive priority

Defenders should prioritize upgrading to version 1.0.0-preview3 or later to resolve this issue.

Recommended defensive actions

• Upgrade to version 1.0.0-preview3 or later
• Review and apply the patch with identifier ccbd12b6108a6a8f0fd5d8b4a9ece3c8a94ba1e4
• Assess exposure and apply necessary mitigations
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source metadata indicate a security vulnerability in a2aproject a2a-dotnet up to 1.0.0-preview2. The vulnerability leads to information exposure through error messages and can be exploited remotely. Upgrading to version 1.0.0-preview3 is recommended.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.