diff --git a/packages/providers/upload-aws-s3/lib/__tests__/getBucketFromUrl.test.js b/packages/providers/upload-aws-s3/lib/__tests__/getBucketFromUrl.test.js
new file mode 100644
index 0000000000..7b253babf1
--- /dev/null
+++ b/packages/providers/upload-aws-s3/lib/__tests__/getBucketFromUrl.test.js
@@ -0,0 +1,43 @@
+'use strict';
+
+const { getBucketFromUrl } = require('../utils');
+
+describe('Test for URLs', () => {
+  test('Virtual hosted style', async () => {
+    const url = 'https://bucket.s3.us-east-1.amazonaws.com/img.png';
+    const { bucket } = getBucketFromUrl(url);
+    expect(bucket).toEqual('bucket');
+  });
+
+  describe('Path style', () => {
+    test('No key', async () => {
+      const url = 'https://s3.us-east-1.amazonaws.com/bucket';
+      const { bucket } = getBucketFromUrl(url);
+      expect(bucket).toEqual('bucket');
+    });
+
+    test('With trailing slash', async () => {
+      const url = 'https://s3.us-east-1.amazonaws.com/bucket/';
+      const { bucket } = getBucketFromUrl(url);
+      expect(bucket).toEqual('bucket');
+    });
+
+    test('With key', async () => {
+      const url = 'https://s3.us-east-1.amazonaws.com/bucket/img.png';
+      const { bucket } = getBucketFromUrl(url);
+      expect(bucket).toEqual('bucket');
+    });
+  });
+
+  test('S3 access point', async () => {
+    const url = 'https://bucket.s3-accesspoint.us-east-1.amazonaws.com';
+    const { bucket } = getBucketFromUrl(url);
+    expect(bucket).toEqual('bucket');
+  });
+
+  test('S3://', async () => {
+    const url = 'S3://bucket/img.png';
+    const { bucket } = getBucketFromUrl(url);
+    expect(bucket).toEqual('bucket');
+  });
+});
diff --git a/packages/providers/upload-aws-s3/lib/index.js b/packages/providers/upload-aws-s3/lib/index.js
index 524ce01abd..331b15c10b 100644
--- a/packages/providers/upload-aws-s3/lib/index.js
+++ b/packages/providers/upload-aws-s3/lib/index.js
@@ -8,6 +8,7 @@
 // Public node modules.
 const get = require('lodash/get');
 const AWS = require('aws-sdk');
+const { getBucketFromUrl } = require('./utils');
 
 function assertUrlProtocol(url) {
   // Regex to test protocol like "http://", "https://"
@@ -66,6 +67,12 @@ module.exports = {
        * @returns {Promise<{url: string}>}
        */
       getSignedUrl(file, customParams = {}) {
+        // Do not sign the url if it does not come from the same bucket.
+        const { bucket } = getBucketFromUrl(file.url);
+        if (bucket !== config.params.Bucket) {
+          return { url: file.url };
+        }
+
         return new Promise((resolve, reject) => {
           const path = file.path ? `${file.path}/` : '';
           const fileKey = `${path}${file.hash}${file.ext}`;
diff --git a/packages/providers/upload-aws-s3/lib/utils.js b/packages/providers/upload-aws-s3/lib/utils.js
new file mode 100644
index 0000000000..b59ff48a0d
--- /dev/null
+++ b/packages/providers/upload-aws-s3/lib/utils.js
@@ -0,0 +1,63 @@
+'use strict';
+
+const ENDPOINT_PATTERN = /^(.+\.)?s3[.-]([a-z0-9-]+)\./;
+
+/**
+ * Parse the bucket name from a URL.
+ * See all URL formats in https://docs.aws.amazon.com/AmazonS3/latest/userguide/access-bucket-intro.html
+ *
+ * @param {string} fileUrl - the URL to parse
+ * @returns {object} result
+ * @returns {string} result.bucket - the bucket name
+ * @returns {string} result.error - if any
+ */
+function getBucketFromUrl(fileUrl) {
+  const uri = new URL(fileUrl);
+
+  // S3://<bucket-name>/<key>
+  if (uri.protocol === 's3:') {
+    const bucket = uri.host;
+
+    if (!bucket) {
+      return { err: `Invalid S3 URI: no bucket: ${uri}` };
+    }
+    return { bucket };
+  }
+
+  if (!uri.host) {
+    return { err: `Invalid S3 URI: no hostname: ${uri}` };
+  }
+
+  const matches = uri.host.match(ENDPOINT_PATTERN);
+  if (!matches) {
+    return { err: `Invalid S3 URI: hostname does not appear to be a valid S3 endpoint: ${uri}` };
+  }
+
+  const prefix = matches[1];
+  // https://s3.amazonaws.com/<bucket-name>
+  if (!prefix) {
+    if (uri.pathname === '/') {
+      return { bucket: null };
+    }
+
+    const index = uri.pathname.indexOf('/', 1);
+
+    // https://s3.amazonaws.com/<bucket-name>
+    if (index === -1) {
+      return { bucket: uri.pathname.substring(1) };
+    }
+
+    // https://s3.amazonaws.com/<bucket-name>/
+    if (index === uri.pathname.length - 1) {
+      return { bucket: uri.pathname.substring(1, index) };
+    }
+
+    // https://s3.amazonaws.com/<bucket-name>/key
+    return { bucket: uri.pathname.substring(1, index) };
+  }
+
+  // https://<bucket-name>.s3.amazonaws.com/
+  return { bucket: prefix.substring(0, prefix.length - 1) };
+}
+
+module.exports = { getBucketFromUrl };