GHSA-vhmw-fwrr-r6c6: AshAi sends unrecognized tool errors verbatim to MCP clients and the model, disclosing internal details
Summary
Generation of Error Message Containing Sensitive Information vulnerability in ash-project ashai allows a caller of an AshAi tool to read internal error details, including module names and data values, by making a tool call fail.
AshAi.ToToolError gained an implementation for Ash.Error.Unknown.UnknownError that returns the error's error field as is, and AshAi.Tool.Errors.format/1 sends that text to MCP clients (tool calls and resource reads in AshAi.Mcp.Server) and to the model in AshAi.ToolLoop. Ash stores the full Exception.format/2 output of a raised exception, or inspect/1 of a bare {:error, term} return, in that field. A tool result that cannot be JSON-encoded raises a Protocol.UndefinedError whose text includes the inspected value, which can be a whole record with fields the tool never returns. None of these errors were logged. The fix logs them under an error id and returns only that id to the caller.
This issue affects ashai: from 1.5.0 before 1.5.1.
Impact
A caller with tool access sends unexpected or malformed tool arguments until a tool fails, then reads the returned error text to learn internal module and function names and the values the code failed on.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
erlang/ash_aito a version that resolves this vulnerability.Fixed in 1.5.1 - Upgrade
Upgrade
ash_aito a version that resolves this vulnerability.Fixed in 1.5.1
Event History
Frequently Asked Questions
Which deployments and users are exposed?
AshAi versions from 1.5.0 before 1.5.1 are affected. Exploitation requires a caller that has access to an AshAi tool.
What does an attacker need to do to obtain leaked data?
The caller sends unexpected or malformed tool arguments until a tool call fails, then reads the returned error text. A result that cannot be JSON-encoded can trigger a Protocol.UndefinedError whose message includes an inspected value.
What information can be disclosed through the error output?
The returned text can disclose internal module and function names and data values. In some cases, it can include an entire record and fields that the tool would not normally return.
Can prior exploitation be identified from application logs?
The affected errors were not logged. The fix logs errors under an error ID and returns only that ID to the caller, but the provided information does not describe retrospective detection for previously exposed errors.