diff --git a/jwcrypto/jwa.py b/jwcrypto/jwa.py
index de7a79f..78361a1 100644
--- a/jwcrypto/jwa.py
+++ b/jwcrypto/jwa.py
@@ -28,6 +28,7 @@
 
 # Implements RFC 7518 - JSON Web Algorithms (JWA)
 
+default_max_pbkdf2_iterations = 16384
 
 class JWAAlgorithm(metaclass=ABCMeta):
 
@@ -588,6 +589,9 @@ def __init__(self):
         self.aeskwmap = {128: _A128KW, 192: _A192KW, 256: _A256KW}
 
     def _get_key(self, alg, key, p2s, p2c):
+        if p2c > default_max_pbkdf2_iterations:
+            raise ValueError('Invalid p2c value, too large')
+
         if not isinstance(key, JWK):
             # backwards compatibility for old interface
             if isinstance(key, bytes):
diff --git a/jwcrypto/tests.py b/jwcrypto/tests.py
index 6069fab..bb2ff10 100644
--- a/jwcrypto/tests.py
+++ b/jwcrypto/tests.py
@@ -2099,6 +2099,18 @@ def test_pbes2_hs256_aeskw_custom_params(self):
         key = jwk.JWK.from_password('password')
         self.assertRaises(ValueError, enc.add_recipient, key)
 
+        # Test p2c iteration checks
+        maxiter = jwa.default_max_pbkdf2_iterations
+        p2cenc = jwe.JWE(plaintext='plain',
+                         protected={"alg": "PBES2-HS256+A128KW",
+                                    "enc": "A256CBC-HS512",
+                                    "p2c": maxiter + 1,
+                                    "p2s": base64url_encode("A" * 16)})
+        with self.assertRaisesRegex(ValueError, 'too large'):
+            p2cenc.add_recipient(key)
+        jwa.default_max_pbkdf2_iterations += 2
+        p2cenc.add_recipient(key)
+
 
 class JWATests(unittest.TestCase):
     def test_jwa_create(self):