diff --git a/packages/aws-cdk/lib/cli.ts b/packages/aws-cdk/lib/cli.ts
index b41bbb1731a54..32dfb3e0dc32f 100644
--- a/packages/aws-cdk/lib/cli.ts
+++ b/packages/aws-cdk/lib/cli.ts
@@ -25,6 +25,7 @@ import { Command, Configuration, Settings } from '../lib/settings';
 import * as version from '../lib/version';
 import { DeploymentMethod } from './api';
 import { enableTracing } from './util/tracing';
+import { checkForPlatformWarnings } from './platform-warnings';
 
 // https://github.com/yargs/yargs/issues/1929
 // https://github.com/evanw/esbuild/issues/1492
@@ -294,6 +295,13 @@ async function initCommandLine() {
   if (argv.ci) {
     setCI(true);
   }
+
+  try {
+    await checkForPlatformWarnings();
+  } catch (e) {
+    debug(`Error while checking for platform warnings: ${e}`);
+  }
+
   debug('CDK toolkit version:', version.DISPLAY_VERSION);
   debug('Command line arguments:', argv);
 
diff --git a/packages/aws-cdk/lib/platform-warnings.ts b/packages/aws-cdk/lib/platform-warnings.ts
new file mode 100644
index 0000000000000..4b364e52969d9
--- /dev/null
+++ b/packages/aws-cdk/lib/platform-warnings.ts
@@ -0,0 +1,41 @@
+import * as os from 'os';
+import * as logging from './logging';
+import * as fs from 'fs-extra';
+
+export async function checkForPlatformWarnings() {
+  if (await hasDockerCopyBug()) {
+    logging.warning('`cdk synth` may hang in Docker on Linux 5.6-5.10. See https://github.com/aws/aws-cdk/issues/21379 for workarounds.');
+  }
+}
+
+async function hasDockerCopyBug() {
+  return await runningInDocker() && os.platform() === 'linux' && isVersionBetween(os.release(), '5.6', '5.10');
+}
+
+async function runningInDocker() {
+  return fs.pathExists('/.dockerenv');
+}
+
+export function isVersionBetween(version: string, lower: string, upper: string) {
+  const ver = splitVersion(version);
+  const lo = splitVersion(lower);
+  const up = splitVersion(upper);
+
+  while (lo.length < ver.length) { lo.push(0); }
+  while (up.length < ver.length) { up.push(9999999); }
+
+  let n = ver.length;
+  for (let i = 0; i < n; i++) {
+    if (lo[i] < ver[i] && ver[i] < up[i]) { return true; }
+    if (lo[i] > ver[i] || ver[i] > up[i]) { return false; }
+  }
+
+  return false;
+
+}
+
+function splitVersion(version: string): number[] {
+  return `${version}`.split('.')
+    .map(x => parseInt(x, 10))
+    .map(x => isNaN(x) ? 0 : x);
+}
diff --git a/packages/aws-cdk/test/platform-warnings.test.ts b/packages/aws-cdk/test/platform-warnings.test.ts
new file mode 100644
index 0000000000000..f2199c2dc7e11
--- /dev/null
+++ b/packages/aws-cdk/test/platform-warnings.test.ts
@@ -0,0 +1,15 @@
+import { isVersionBetween } from '../lib/platform-warnings';
+
+
+test.each([
+  ['2.1', false],
+  ['2.2', true],
+  ['2', false],
+  ['3', true],
+  ['4', false],
+  ['4.3', true],
+  ['4.3', true],
+  ['4.2.294-220.533.amzn2.x86_64', true],
+])('%p is in range: %p', (version, expected) => {
+  expect(isVersionBetween(version, '2.1.0.6', '4.9.2')).toEqual(expected);
+});
\ No newline at end of file