diff --git a/crypto/dh/dh_ameth.c b/crypto/dh/dh_ameth.c
index 222cb20b4248b42f2837a5d817a529cb71c067d1..b7b37177c160174b06a390330e215ec4bc4383d0 100644
--- a/crypto/dh/dh_ameth.c
+++ b/crypto/dh/dh_ameth.c
@@ -437,7 +437,7 @@ static int dh_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 
 static int dh_missing_parameters(const EVP_PKEY *a)
 {
-    if (!a->pkey.dh->p || !a->pkey.dh->g)
+    if (a->pkey.dh == NULL || a->pkey.dh->p == NULL || a->pkey.dh->g == NULL)
         return 1;
     return 0;
 }
diff --git a/crypto/dsa/dsa_ameth.c b/crypto/dsa/dsa_ameth.c
index 1bb11a9ed597761b134ffc170d3c18e6273f62fd..a53247c0748920164a4d1a4c9b99b68853d90d05 100644
--- a/crypto/dsa/dsa_ameth.c
+++ b/crypto/dsa/dsa_ameth.c
@@ -266,7 +266,7 @@ static int dsa_missing_parameters(const EVP_PKEY *pkey)
 {
     DSA *dsa;
     dsa = pkey->pkey.dsa;
-    if ((dsa->p == NULL) || (dsa->q == NULL) || (dsa->g == NULL))
+    if (dsa == NULL || dsa->p == NULL || dsa->q == NULL || dsa->g == NULL)
         return 1;
     return 0;
 }
diff --git a/crypto/ec/ec_ameth.c b/crypto/ec/ec_ameth.c
index 684da95ab208f50119e279c451fa8ccaacad5225..6567a2f398cfcc219c2c250e0e5796653e31e081 100644
--- a/crypto/ec/ec_ameth.c
+++ b/crypto/ec/ec_ameth.c
@@ -292,7 +292,7 @@ static int ec_security_bits(const EVP_PKEY *pkey)
 
 static int ec_missing_parameters(const EVP_PKEY *pkey)
 {
-    if (EC_KEY_get0_group(pkey->pkey.ec) == NULL)
+    if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL)
         return 1;
     return 0;
 }
diff --git a/crypto/evp/p_lib.c b/crypto/evp/p_lib.c
index 0b7884f9e569d11c37059cd48e28f2464e1aa4b5..0b50d3210e551dc7d35f4b4f9f0b4249547a1657 100644
--- a/crypto/evp/p_lib.c
+++ b/crypto/evp/p_lib.c
@@ -84,6 +84,14 @@ int EVP_PKEY_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
         EVPerr(EVP_F_EVP_PKEY_COPY_PARAMETERS, EVP_R_MISSING_PARAMETERS);
         goto err;
     }
+
+    if (!EVP_PKEY_missing_parameters(to)) {
+        if (EVP_PKEY_cmp_parameters(to, from) == 1)
+            return 1;
+        EVPerr(EVP_F_EVP_PKEY_COPY_PARAMETERS, EVP_R_DIFFERENT_PARAMETERS);
+        return 0;
+    }
+
     if (from->ameth && from->ameth->param_copy)
         return from->ameth->param_copy(to, from);
  err:
diff --git a/doc/crypto/EVP_PKEY_cmp.pod b/doc/crypto/EVP_PKEY_cmp.pod
index 4e1f78bed16167e4388d5ff5b99805875f07014e..7c9e582a81a44616fe854b39c8adf5749609aea6 100644
--- a/doc/crypto/EVP_PKEY_cmp.pod
+++ b/doc/crypto/EVP_PKEY_cmp.pod
@@ -21,7 +21,9 @@ parameters of B<pkey> are missing and 0 if they are present or the algorithm
 doesn't use parameters.
 
 The function EVP_PKEY_copy_parameters() copies the parameters from key
-B<from> to key B<to>.
+B<from> to key B<to>. An error is returned if the parameters are missing in
+B<from> or present in both B<from> and B<to> and mismatch. If the parameters
+in B<from> and B<to> are both present and match this function has no effect.
 
 The function EVP_PKEY_cmp_parameters() compares the parameters of keys
 B<a> and B<b>.