dotnet/aspnetcore · error

Invalid payload for Ping message.

Error message

Invalid payload for Ping message.

What it means

Thrown by _createPingMessage when the decoded properties array has fewer than 1 element. A Ping is the simplest frame ([MessageType.Ping]) and only needs the type byte, so hitting this means the properties array was unexpectedly empty after the type was already read as messageType — essentially an unreachable defensive guard for a degenerate decode result.

Source

Thrown at src/SignalR/clients/ts/signalr-protocol-msgpack/src/MessagePackHubProtocol.ts:178

    private _createCloseMessage(properties: any[]): HubMessage {
        // check minimum length to allow protocol to add items to the end of objects in future releases
        if (properties.length < 2) {
            throw new Error("Invalid payload for Close message.");
        }

        return {
            // Close messages have no headers.
            allowReconnect: properties.length >= 3 ? properties[2] : undefined,
            error: properties[1],
            type: MessageType.Close,
        } as HubMessage;
    }

    private _createPingMessage(properties: any[]): HubMessage {
        // check minimum length to allow protocol to add items to the end of objects in future releases
        if (properties.length < 1) {
            throw new Error("Invalid payload for Ping message.");
        }

        return {
            // Ping messages have no headers.
            type: MessageType.Ping,
        } as HubMessage;
    }

    private _createInvocationMessage(headers: MessageHeaders, properties: any[]): InvocationMessage {
        // check minimum length to allow protocol to add items to the end of objects in future releases
        if (properties.length < 5) {
            throw new Error("Invalid payload for Invocation message.");
        }

        const invocationId = properties[2] as string;
        if (invocationId) {
            return {
                arguments: properties[4],

View on GitHub (pinned to 294cab2f9b)

Solutions

1. Treat as unrecoverable corruption: log and reconnect.
2. Ensure @msgpack/msgpack is at the supported version and not patched/overridden via MessagePackOptions.
3. Verify the binary buffer hasn't been mutated concurrently (no shared ArrayBuffer being written from another thread).
4. Capture the frame bytes for forensic analysis.

try {
  const messages = protocol.parseMessages(buffer, logger);
} catch (e) {
  if (/Ping message/.test(e.message)) {
    logger.log(LogLevel.Error, 'Degenerate Ping frame; reconnecting.');
    await connection.start();
  } else throw e;
}

When it happens

Trigger: Effectively only reachable if the msgpack decoder returns an array shorter than the one used to read messageType, which cannot happen in normal flow; in practice indicates memory corruption or a patched decoder.

Common situations: Not seen in normal operation; appears only with a tampered/misbehaving msgpack decoder or heavily corrupted input where the array length is inconsistent.

Related errors

• Invalid payload for Close message.
• Invalid payload.
• Invalid payload for Invocation message.
• Invalid payload for StreamItem message.
• Invalid payload for Completion message.

AI-assisted analysis of dotnet/aspnetcore@294cab2f9b (2026-08-06). Data as JSON: /api/errors/c3febb8f7be4cd86. Report an issue: GitHub.