Validate static_map_image_tool style path

CHANGELOG.md

@@ -1,5 +1,10 @@
 ## Unreleased
 
+### Security
+
+- **static_map_image_tool**: Validate `style` parameter against `username/style-id` format to prevent path traversal attacks where a crafted style value (e.g., `../../tokens/v2`) could escape the `/styles/v1/` URL path and access arbitrary Mapbox API endpoints using the server operator's token
+- **static_map_image_tool**: Remove access token from URL returned in text content — the token is only used internally for the HTTP fetch and the MCP Apps iframe URL, not exposed to the model context
+
 ### Exports
 
 - Added `getAllTools` to `@mapbox/mcp-server/tools` subpath export for batch access to all registered tools

src/tools/static-map-image-tool/StaticMapImageTool.input.schema.ts

@@ -339,10 +339,14 @@ export const StaticMapImageInputSchema = z.object({
     ),
   style: z
     .string()
+    .regex(
+      /^[a-zA-Z0-9_-]+\/[a-zA-Z0-9_-]+$/,
+      'Style must be in the format username/style-id using only alphanumeric characters, hyphens, and underscores (e.g., mapbox/streets-v12)'
+    )
     .optional()
     .default('mapbox/streets-v12')
     .describe(
-      'Mapbox style ID (e.g., mapbox/streets-v12, mapbox/satellite-v9, mapbox/dark-v11)'
+      'Mapbox style ID in the format username/style-id (e.g., mapbox/streets-v12, mapbox/satellite-v9, mapbox/dark-v11)'
     ),
   highDensity: z
     .boolean()

src/tools/static-map-image-tool/StaticMapImageTool.ts

@@ -108,7 +108,14 @@ export class StaticMapImageTool extends MapboxApiBasedTool<
     }
 
     const density = input.highDensity ? '@2x' : '';
-    const url = `${MapboxApiBasedTool.mapboxApiEndpoint}styles/v1/${input.style}/static/${overlayString}${lng},${lat},${input.zoom}/${width}x${height}${density}?access_token=${accessToken}`;
+    const encodedStyle = input.style
+      .split('/')
+      .map(encodeURIComponent)
+      .join('/');
+    const url = `${MapboxApiBasedTool.mapboxApiEndpoint}styles/v1/${encodedStyle}/static/${overlayString}${lng},${lat},${input.zoom}/${width}x${height}${density}?access_token=${accessToken}`;
+
+    // Public URL without credentials for returning to the model
+    const publicUrl = `${MapboxApiBasedTool.mapboxApiEndpoint}styles/v1/${encodedStyle}/static/${overlayString}${lng},${lat},${input.zoom}/${width}x${height}${density}`;
 
     // Fetch and encode image as base64 for clients without MCP Apps support
     const response = await this.httpRequest(url);
@@ -125,10 +132,11 @@ export class StaticMapImageTool extends MapboxApiBasedTool<
     const mimeType = isRasterStyle ? 'image/jpeg' : 'image/png';
 
     // content[0] MUST be the URL text — MCP Apps UI finds it via content.find(c => c.type === 'text')
+    // Use public URL (without credentials) to avoid leaking the access token
     const content: CallToolResult['content'] = [
       {
         type: 'text',
-        text: url
+        text: publicUrl
       },
       {
         type: 'image',

test/tools/static-map-image-tool/StaticMapImageTool.test.ts

@@ -53,7 +53,7 @@ describe('StaticMapImageTool', () => {
       );
       expect(textContent.text).toContain('-74.006,40.7128,10');
       expect(textContent.text).toContain('800x600');
-      expect(textContent.text).toContain('access_token=');
+      expect(textContent.text).not.toContain('access_token=');
     } finally {
       // Restore environment variable
       if (originalEnv !== undefined) {
@@ -152,7 +152,7 @@ describe('StaticMapImageTool', () => {
     expect(url).toContain('styles/v1/mapbox/dark-v10/static/');
     expect(url).toContain('-122.4194,37.7749,15');
     expect(url).toContain('1024x768');
-    expect(url).toContain('access_token=');
+    expect(url).not.toContain('access_token=');
   });
 
   it('uses default style when not specified', async () => {
@@ -168,6 +168,30 @@ describe('StaticMapImageTool', () => {
     expect(url).toContain('styles/v1/mapbox/streets-v12/static/');
   });
 
+  it('rejects style values with path traversal patterns', async () => {
+    const { httpRequest } = setupHttpRequest();
+    const tool = new StaticMapImageTool({ httpRequest });
+
+    const traversalPayloads = [
+      '../../tokens/v2',
+      '../styles',
+      'mapbox/../../../tokens',
+      '/etc/passwd',
+      'mapbox/streets-v12/../../tokens'
+    ];
+
+    for (const style of traversalPayloads) {
+      await expect(
+        tool.run({
+          center: { longitude: -74, latitude: 40 },
+          zoom: 10,
+          size: { width: 600, height: 400 },
+          style
+        })
+      ).resolves.toMatchObject({ isError: true });
+    }
+  });
+
   it('validates coordinate constraints', async () => {
     const { httpRequest } = setupHttpRequest();
     const tool = new StaticMapImageTool({ httpRequest });