BREW-openclaw-cli-CVE-2026-3689 — OpenClaw Canvas Path Traversal Information Disclosure Vulnerability

Affected: Homebrew: openclaw-cli

ZDI-CAN-29312: OpenClaw Canvas Path Traversal Information Disclosure Vulnerability

-- ABSTRACT -------------------------------------

Trend Micro's Zero Day Initiative has identified a vulnerability affecting the following products: OpenClaw - OpenClaw

-- VULNERABILITY DETAILS ------------------------ * Version tested: openclaw 2026.2.17 * Platform tested: macOS 26.3

---

# Analysis

## Description

The OpenClaw gateway's `canvas` tool accepts an `a2ui_push` action with a `jsonlPath` parameter that specifies a filesystem path to read. The gateway reads this file using `fs.readFile()` with no path validation, canonicalization, or directory restriction. An authenticated attacker can supply an arbitrary absolute or relative path to read any file accessible to the gateway process.

The file contents are forwarded to the connected node client via the `canvas.a2ui.pushJSONL` WebSocket command. The gateway itself returns `{ ok: true }` to the HTTP caller, confirming the file was read and transmitted.

## Root Cause

In `src/agents/tools/canvas-tool.ts`, the `a2ui_push` action handler reads a file from disk without any path restrictions:

```typescript case "a2ui_push": { const jsonl = typeof params.jsonl === "string" && params.jsonl.trim() ? params.jsonl : typeof params.jsonlPath === "string" && params.jsonlPath.trim() ? await fs.readFile(params.jsonlPath.trim(), "utf8") // <-- NO PATH VALIDATION : ""; if (!jsonl.trim()) { throw new Error…

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BREW-openclaw-cli-CVE-2026-3689 — OpenClaw Canvas Path Traversal Information Disclosure Vulnerability