diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 1855aa3a..4b7fa2ce 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -56,6 +56,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: dart-lang/setup-dart@v1
+      - name: Install Valgrind
+        run: |
+          sudo apt-get update -y
+          sudo apt-get install -y valgrind
       - run: dart pub get --no-example
       - run: xvfb-run dart test --exclude-tags browser-interop -p vm,chrome,firefox -c dart2js,dart2wasm
   macos:
diff --git a/test/ffi/valgrind_target.dart b/test/ffi/valgrind_target.dart
new file mode 100644
index 00000000..b30291e0
--- /dev/null
+++ b/test/ffi/valgrind_target.dart
@@ -0,0 +1,322 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'dart:async';
+import 'dart:typed_data';
+
+import 'package:webcrypto/webcrypto.dart';
+
+/// Exercises FFI ownership and cleanup paths while Valgrind inspects the
+/// process. This deliberately avoids `package:test` so the monitored process
+/// contains only the crypto workload and its memory-pressure allocations.
+Future<void> main() async {
+  await _exerciseSymmetricOperations();
+  await _exerciseAsymmetricKeyOwnership();
+  await _exerciseCleanupAfterFailedImports();
+  // ignore: avoid_print
+  print('Cryptographic operations survived memory pressure.');
+}
+
+Future<void> _exerciseSymmetricOperations() async {
+  for (var i = 0; i < 16; i++) {
+    final message = _bytes(64 + i, i);
+    final digest = await Hash.sha256.digestBytes(message);
+    _expectLength(digest, 32, 'SHA-256 digest');
+
+    final aesKeyData = _bytes(16, 100 + i);
+    final aesKey = await AesGcmSecretKey.importRawKey(aesKeyData);
+    final iv = _bytes(12, 200 + i);
+    final additionalData = _bytes(8, 300 + i);
+    final ciphertext = await aesKey.encryptBytes(
+      message,
+      iv,
+      additionalData: additionalData,
+    );
+    final plaintext = await aesKey.decryptBytes(
+      ciphertext,
+      iv,
+      additionalData: additionalData,
+    );
+    _expectBytes(plaintext, message, 'AES-GCM plaintext');
+    _expectBytes(await aesKey.exportRawKey(), aesKeyData, 'AES-GCM raw key');
+
+    final aesJwk = await aesKey.exportJsonWebKey();
+    final aesJwkKey = await AesGcmSecretKey.importJsonWebKey(aesJwk);
+    _expectBytes(await aesJwkKey.exportRawKey(), aesKeyData, 'AES-GCM JWK key');
+
+    final hmacKeyData = _bytes(32, 400 + i);
+    final hmacKey = await HmacSecretKey.importRawKey(hmacKeyData, Hash.sha256);
+    final signature = await hmacKey.signBytes(message);
+    _check(
+      await hmacKey.verifyBytes(signature, message),
+      'HMAC signature verification failed.',
+    );
+    _expectBytes(await hmacKey.exportRawKey(), hmacKeyData, 'HMAC raw key');
+
+    final hmacJwk = await hmacKey.exportJsonWebKey();
+    final hmacJwkKey = await HmacSecretKey.importJsonWebKey(
+      hmacJwk,
+      Hash.sha256,
+    );
+    _check(
+      await hmacJwkKey.verifyBytes(signature, message),
+      'HMAC JWK signature verification failed.',
+    );
+
+    if (i.isEven) {
+      await _applyMemoryPressure();
+    }
+  }
+}
+
+Future<void> _exerciseAsymmetricKeyOwnership() async {
+  for (var i = 0; i < 4; i++) {
+    final alice = await EcdhPrivateKey.generateKey(EllipticCurve.p256);
+    final bob = await EcdhPrivateKey.generateKey(EllipticCurve.p256);
+
+    final aliceSecret = await alice.privateKey.deriveBits(256, bob.publicKey);
+    final bobSecret = await bob.privateKey.deriveBits(256, alice.publicKey);
+    _expectBytes(aliceSecret, bobSecret, 'ECDH shared secret');
+
+    final privatePkcs8 = await alice.privateKey.exportPkcs8Key();
+    final publicSpki = await alice.publicKey.exportSpkiKey();
+    final importedPrivate = await EcdhPrivateKey.importPkcs8Key(
+      privatePkcs8,
+      EllipticCurve.p256,
+    );
+    final importedPublic = await EcdhPublicKey.importSpkiKey(
+      publicSpki,
+      EllipticCurve.p256,
+    );
+    _expectLength(
+      await importedPrivate.deriveBits(256, importedPublic),
+      32,
+      'Imported ECDH shared secret',
+    );
+
+    final privateJwk = await alice.privateKey.exportJsonWebKey();
+    final publicJwk = await alice.publicKey.exportJsonWebKey();
+    final importedPrivateJwk = await EcdhPrivateKey.importJsonWebKey(
+      privateJwk,
+      EllipticCurve.p256,
+    );
+    final importedPublicJwk = await EcdhPublicKey.importJsonWebKey(
+      publicJwk,
+      EllipticCurve.p256,
+    );
+    _expectLength(
+      await importedPrivateJwk.deriveBits(256, importedPublicJwk),
+      32,
+      'Imported ECDH JWK shared secret',
+    );
+
+    await _applyMemoryPressure();
+  }
+
+  final rsa = await RsaOaepPrivateKey.generateKey(
+    2048,
+    BigInt.from(65537),
+    Hash.sha256,
+  );
+  final privatePkcs8 = await rsa.privateKey.exportPkcs8Key();
+  final publicSpki = await rsa.publicKey.exportSpkiKey();
+  final privateKey = await RsaOaepPrivateKey.importPkcs8Key(
+    privatePkcs8,
+    Hash.sha256,
+  );
+  final publicKey = await RsaOaepPublicKey.importSpkiKey(
+    publicSpki,
+    Hash.sha256,
+  );
+
+  for (var i = 0; i < 3; i++) {
+    final message = _bytes(32 + i, 500 + i);
+    final label = _bytes(8, 600 + i);
+    final ciphertext = await publicKey.encryptBytes(message, label: label);
+    _expectBytes(
+      await privateKey.decryptBytes(ciphertext, label: label),
+      message,
+      'RSA-OAEP plaintext',
+    );
+
+    final privateJwk = await privateKey.exportJsonWebKey();
+    final publicJwk = await publicKey.exportJsonWebKey();
+    final privateJwkKey = await RsaOaepPrivateKey.importJsonWebKey(
+      privateJwk,
+      Hash.sha256,
+    );
+    final publicJwkKey = await RsaOaepPublicKey.importJsonWebKey(
+      publicJwk,
+      Hash.sha256,
+    );
+    final jwkCiphertext = await publicJwkKey.encryptBytes(
+      message,
+      label: label,
+    );
+    _expectBytes(
+      await privateJwkKey.decryptBytes(jwkCiphertext, label: label),
+      message,
+      'RSA-OAEP JWK plaintext',
+    );
+
+    await _applyMemoryPressure();
+  }
+}
+
+Future<void> _exerciseCleanupAfterFailedImports() async {
+  final ecdh = await EcdhPrivateKey.generateKey(EllipticCurve.p256);
+  final privatePkcs8 = await ecdh.privateKey.exportPkcs8Key();
+  final publicSpki = await ecdh.publicKey.exportSpkiKey();
+
+  await _expectFormatException(
+    EcdhPrivateKey.importPkcs8Key(
+      _withCorruptedByte(privatePkcs8),
+      EllipticCurve.p256,
+    ),
+    'corrupt ECDH PKCS8 import',
+  );
+  await _expectFormatException(
+    EcdhPublicKey.importSpkiKey(
+      _withCorruptedByte(publicSpki),
+      EllipticCurve.p256,
+    ),
+    'corrupt ECDH SPKI import',
+  );
+
+  await _applyMemoryPressure();
+
+  final validPrivate = await EcdhPrivateKey.importPkcs8Key(
+    privatePkcs8,
+    EllipticCurve.p256,
+  );
+  final validPublic = await EcdhPublicKey.importSpkiKey(
+    publicSpki,
+    EllipticCurve.p256,
+  );
+  _expectLength(
+    await validPrivate.deriveBits(256, validPublic),
+    32,
+    'Valid ECDH operation after failed imports',
+  );
+
+  final rsa = await RsaOaepPrivateKey.generateKey(
+    2048,
+    BigInt.from(65537),
+    Hash.sha256,
+  );
+  final rsaPrivatePkcs8 = await rsa.privateKey.exportPkcs8Key();
+  final rsaPublicSpki = await rsa.publicKey.exportSpkiKey();
+
+  await _expectFormatException(
+    RsaOaepPrivateKey.importPkcs8Key(
+      _withCorruptedByte(rsaPrivatePkcs8),
+      Hash.sha256,
+    ),
+    'corrupt RSA PKCS8 import',
+  );
+  await _expectFormatException(
+    RsaOaepPublicKey.importSpkiKey(
+      _withCorruptedByte(rsaPublicSpki),
+      Hash.sha256,
+    ),
+    'corrupt RSA SPKI import',
+  );
+
+  await _applyMemoryPressure();
+
+  final validRsaPrivate = await RsaOaepPrivateKey.importPkcs8Key(
+    rsaPrivatePkcs8,
+    Hash.sha256,
+  );
+  final validRsaPublic = await RsaOaepPublicKey.importSpkiKey(
+    rsaPublicSpki,
+    Hash.sha256,
+  );
+  final message = _bytes(32, 700);
+  final ciphertext = await validRsaPublic.encryptBytes(message);
+  _expectBytes(
+    await validRsaPrivate.decryptBytes(ciphertext),
+    message,
+    'Valid RSA operation after failed imports',
+  );
+}
+
+Uint8List _bytes(int length, int seed) {
+  var state = seed & 0x7fffffff;
+  final bytes = Uint8List(length);
+  for (var i = 0; i < bytes.length; i++) {
+    state = (state * 1103515245 + 12345) & 0x7fffffff;
+    bytes[i] = state & 0xff;
+  }
+  return bytes;
+}
+
+Uint8List _withCorruptedByte(List<int> bytes) {
+  final corrupted = Uint8List.fromList(bytes);
+  corrupted[0] ^= 0xff;
+  return corrupted;
+}
+
+Future<void> _expectFormatException(
+  Future<Object?> operation,
+  String description,
+) async {
+  try {
+    await operation;
+  } on FormatException {
+    return;
+  }
+  throw StateError('$description did not throw FormatException.');
+}
+
+void _expectBytes(List<int> actual, List<int> expected, String description) {
+  if (actual.length != expected.length) {
+    throw StateError(
+      '$description had length ${actual.length}; expected ${expected.length}.',
+    );
+  }
+  for (var i = 0; i < actual.length; i++) {
+    if (actual[i] != expected[i]) {
+      throw StateError('$description differed at byte $i.');
+    }
+  }
+}
+
+void _expectLength(List<int> value, int length, String description) {
+  if (value.length != length) {
+    throw StateError(
+      '$description had length ${value.length}; expected $length.',
+    );
+  }
+}
+
+void _check(bool condition, String message) {
+  if (!condition) {
+    throw StateError(message);
+  }
+}
+
+Future<void> _applyMemoryPressure() async {
+  final garbage = <Uint8List>[];
+  var checksum = 0;
+  for (var i = 0; i < 128; i++) {
+    final block = Uint8List(4096);
+    block[0] = i;
+    checksum ^= block[0];
+    garbage.add(block);
+  }
+  _check(garbage.length == 128, 'Memory-pressure allocation was incomplete.');
+  _check(checksum >= 0, 'Memory-pressure checksum was invalid.');
+  await Future<void>.delayed(Duration.zero);
+}
diff --git a/test/ffi/valgrind_test.dart b/test/ffi/valgrind_test.dart
new file mode 100644
index 00000000..dada26f1
--- /dev/null
+++ b/test/ffi/valgrind_test.dart
@@ -0,0 +1,57 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/// Runs [valgrind_target.dart] under Valgrind when the test suite runs on
+/// Linux. Other platforms, and Linux environments without Valgrind, skip it.
+@TestOn('vm')
+@Timeout(Duration(minutes: 3))
+library;
+
+import 'dart:io';
+
+import 'package:test/test.dart';
+
+void main() {
+  test('FFI operations are memory-safe under Valgrind', () async {
+    if (!Platform.isLinux) {
+      markTestSkipped('Valgrind testing is only supported on Linux.');
+      return;
+    }
+
+    final valgrind = Process.runSync('which', ['valgrind']);
+    if (valgrind.exitCode != 0) {
+      markTestSkipped('Valgrind is not installed.');
+      return;
+    }
+
+    final result = await Process.run('valgrind', [
+      '--tool=memcheck',
+      '--leak-check=full',
+      '--show-leak-kinds=definite,possible',
+      '--errors-for-leak-kinds=definite',
+      '--track-origins=yes',
+      '--error-exitcode=1',
+      Platform.resolvedExecutable,
+      'run',
+      'test/ffi/valgrind_target.dart',
+    ]);
+
+    expect(
+      result.exitCode,
+      0,
+      reason:
+          'Valgrind failed.\nstdout:\n${result.stdout}\nstderr:\n${result.stderr}',
+    );
+  });
+}