diff -up openssl-3.0.1/crypto/ec/ec_asn1.c.disable_explicit_ec openssl-3.0.1/crypto/ec/ec_asn1.c
--- openssl-3.0.1/crypto/ec/ec_asn1.c.disable_explicit_ec	2022-03-22 13:10:45.718077845 +0100
+++ openssl-3.0.1/crypto/ec/ec_asn1.c	2022-03-22 13:12:46.626599016 +0100
@@ -895,6 +895,12 @@ EC_GROUP *d2i_ECPKParameters(EC_GROUP **
     if (params->type == ECPKPARAMETERS_TYPE_EXPLICIT)
         group->decoded_from_explicit_params = 1;
 
+    if (EC_GROUP_check_named_curve(group, 0, NULL) == NID_undef) {
+        EC_GROUP_free(group);
+        ECPKPARAMETERS_free(params);
+        return NULL;
+    }
+
     if (a) {
         EC_GROUP_free(*a);
         *a = group;
@@ -954,6 +959,11 @@ EC_KEY *d2i_ECPrivateKey(EC_KEY **a, con
         goto err;
     }
 
+    if (EC_GROUP_check_named_curve(ret->group, 0, NULL) == NID_undef) {
+        ERR_raise(ERR_LIB_EC, EC_R_UNKNOWN_GROUP);
+        goto err;
+    }
+
     ret->version = priv_key->version;
 
     if (priv_key->privateKey) {
diff --git a/crypto/ec/ec_lib.c b/crypto/ec/ec_lib.c
index a84e088c19..6c37bf78ae 100644
--- a/crypto/ec/ec_lib.c
+++ b/crypto/ec/ec_lib.c
@@ -1724,6 +1724,11 @@ EC_GROUP *EC_GROUP_new_from_params(const OSSL_PARAM params[],
         goto err;
     }
     if (named_group == group) {
+        if (EC_GROUP_check_named_curve(group, 0, NULL) == NID_undef) {
+            ERR_raise(ERR_LIB_EC, EC_R_UNKNOWN_GROUP);
+            goto err;
+        }
+#if 0
         /*
          * If we did not find a named group then the encoding should be explicit
          * if it was specified
@@ -1739,6 +1744,7 @@ EC_GROUP *EC_GROUP_new_from_params(const OSSL_PARAM params[],
             goto err;
         }
         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_EXPLICIT_CURVE);
+#endif
     } else {
         EC_GROUP_free(group);
         group = named_group;
diff --git a/test/ectest.c b/test/ectest.c
index 4890b0555e..e11aec5b3b 100644
--- a/test/ectest.c
+++ b/test/ectest.c
@@ -2301,10 +2301,11 @@ static int do_test_custom_explicit_fromdata(EC_GROUP *group, BN_CTX *ctx,
     if (!TEST_ptr(params = OSSL_PARAM_BLD_to_param(bld))
         || !TEST_ptr(pctx = EVP_PKEY_CTX_new_from_name(NULL, "EC", NULL))
         || !TEST_int_gt(EVP_PKEY_fromdata_init(pctx), 0)
-        || !TEST_int_gt(EVP_PKEY_fromdata(pctx, &pkeyparam,
+        || !TEST_int_le(EVP_PKEY_fromdata(pctx, &pkeyparam,
                                           EVP_PKEY_KEY_PARAMETERS, params), 0))
         goto err;
-
+/* As creating the key should fail, the rest of the test is pointless */
+# if 0
     /*- Check that all the set values are retrievable -*/
 
     /* There should be no match to a group name since the generator changed */
@@ -2433,6 +2434,7 @@ static int do_test_custom_explicit_fromdata(EC_GROUP *group, BN_CTX *ctx,
 #endif
         )
         goto err;
+#endif
     ret = 1;
 err:
     BN_free(order_out);
@@ -2714,21 +2716,21 @@ static int custom_params_test(int id)
 
     /* Compute keyexchange in both directions */
     if (!TEST_ptr(pctx1 = EVP_PKEY_CTX_new(pkey1, NULL))
-            || !TEST_int_eq(EVP_PKEY_derive_init(pctx1), 1)
-            || !TEST_int_eq(EVP_PKEY_derive_set_peer(pctx1, pkey2), 1)
+            || !TEST_int_le(EVP_PKEY_derive_init(pctx1), 0)
+/*          || !TEST_int_eq(EVP_PKEY_derive_set_peer(pctx1, pkey2), 1)
             || !TEST_int_eq(EVP_PKEY_derive(pctx1, NULL, &sslen), 1)
             || !TEST_int_gt(bsize, sslen)
-            || !TEST_int_eq(EVP_PKEY_derive(pctx1, buf1, &sslen), 1))
+            || !TEST_int_eq(EVP_PKEY_derive(pctx1, buf1, &sslen), 1)*/)
         goto err;
     if (!TEST_ptr(pctx2 = EVP_PKEY_CTX_new(pkey2, NULL))
-            || !TEST_int_eq(EVP_PKEY_derive_init(pctx2), 1)
-            || !TEST_int_eq(EVP_PKEY_derive_set_peer(pctx2, pkey1), 1)
+            || !TEST_int_le(EVP_PKEY_derive_init(pctx2), 1)
+/*          || !TEST_int_eq(EVP_PKEY_derive_set_peer(pctx2, pkey1), 1)
             || !TEST_int_eq(EVP_PKEY_derive(pctx2, NULL, &t), 1)
             || !TEST_int_gt(bsize, t)
             || !TEST_int_le(sslen, t)
-            || !TEST_int_eq(EVP_PKEY_derive(pctx2, buf2, &t), 1))
+            || !TEST_int_eq(EVP_PKEY_derive(pctx2, buf2, &t), 1) */)
         goto err;
-
+#if 0
     /* Both sides should expect the same shared secret */
     if (!TEST_mem_eq(buf1, sslen, buf2, t))
         goto err;
@@ -2780,7 +2782,7 @@ static int custom_params_test(int id)
             /* compare with previous result */
             || !TEST_mem_eq(buf1, t, buf2, sslen))
         goto err;
-
+#endif
     ret = 1;
 
  err:
diff -up openssl-3.0.1/test/endecode_test.c.disable_explicit_ec openssl-3.0.1/test/endecode_test.c
--- openssl-3.0.1/test/endecode_test.c.disable_explicit_ec	2022-03-21 16:55:46.005558779 +0100
+++ openssl-3.0.1/test/endecode_test.c	2022-03-21 16:56:12.636792762 +0100
@@ -57,7 +57,7 @@ static BN_CTX *bnctx = NULL;
 static OSSL_PARAM_BLD *bld_prime_nc = NULL;
 static OSSL_PARAM_BLD *bld_prime = NULL;
 static OSSL_PARAM *ec_explicit_prime_params_nc = NULL;
-static OSSL_PARAM *ec_explicit_prime_params_explicit = NULL;
+/*static OSSL_PARAM *ec_explicit_prime_params_explicit = NULL;*/
 
 # ifndef OPENSSL_NO_EC2M
 static OSSL_PARAM_BLD *bld_tri_nc = NULL;
@@ -990,9 +990,9 @@ IMPLEMENT_TEST_SUITE_LEGACY(EC, "EC")
 DOMAIN_KEYS(ECExplicitPrimeNamedCurve);
 IMPLEMENT_TEST_SUITE(ECExplicitPrimeNamedCurve, "EC", 1)
 IMPLEMENT_TEST_SUITE_LEGACY(ECExplicitPrimeNamedCurve, "EC")
-DOMAIN_KEYS(ECExplicitPrime2G);
-IMPLEMENT_TEST_SUITE(ECExplicitPrime2G, "EC", 0)
-IMPLEMENT_TEST_SUITE_LEGACY(ECExplicitPrime2G, "EC")
+/*DOMAIN_KEYS(ECExplicitPrime2G);*/
+/*IMPLEMENT_TEST_SUITE(ECExplicitPrime2G, "EC", 0)*/
+/*IMPLEMENT_TEST_SUITE_LEGACY(ECExplicitPrime2G, "EC")*/
 # ifndef OPENSSL_NO_EC2M
 DOMAIN_KEYS(ECExplicitTriNamedCurve);
 IMPLEMENT_TEST_SUITE(ECExplicitTriNamedCurve, "EC", 1)
@@ -1318,7 +1318,7 @@ int setup_tests(void)
         || !create_ec_explicit_prime_params_namedcurve(bld_prime_nc)
         || !create_ec_explicit_prime_params(bld_prime)
         || !TEST_ptr(ec_explicit_prime_params_nc = OSSL_PARAM_BLD_to_param(bld_prime_nc))
-        || !TEST_ptr(ec_explicit_prime_params_explicit = OSSL_PARAM_BLD_to_param(bld_prime))
+/*        || !TEST_ptr(ec_explicit_prime_params_explicit = OSSL_PARAM_BLD_to_param(bld_prime))*/
 # ifndef OPENSSL_NO_EC2M
         || !TEST_ptr(bld_tri_nc = OSSL_PARAM_BLD_new())
         || !TEST_ptr(bld_tri = OSSL_PARAM_BLD_new())
@@ -1346,7 +1346,7 @@ int setup_tests(void)
     TEST_info("Generating EC keys...");
     MAKE_DOMAIN_KEYS(EC, "EC", EC_params);
     MAKE_DOMAIN_KEYS(ECExplicitPrimeNamedCurve, "EC", ec_explicit_prime_params_nc);
-    MAKE_DOMAIN_KEYS(ECExplicitPrime2G, "EC", ec_explicit_prime_params_explicit);
+/*    MAKE_DOMAIN_KEYS(ECExplicitPrime2G, "EC", ec_explicit_prime_params_explicit);*/
 # ifndef OPENSSL_NO_EC2M
     MAKE_DOMAIN_KEYS(ECExplicitTriNamedCurve, "EC", ec_explicit_tri_params_nc);
     MAKE_DOMAIN_KEYS(ECExplicitTri2G, "EC", ec_explicit_tri_params_explicit);
@@ -1389,8 +1389,8 @@ int setup_tests(void)
         ADD_TEST_SUITE_LEGACY(EC);
         ADD_TEST_SUITE(ECExplicitPrimeNamedCurve);
         ADD_TEST_SUITE_LEGACY(ECExplicitPrimeNamedCurve);
-        ADD_TEST_SUITE(ECExplicitPrime2G);
-        ADD_TEST_SUITE_LEGACY(ECExplicitPrime2G);
+/*        ADD_TEST_SUITE(ECExplicitPrime2G);*/
+/*        ADD_TEST_SUITE_LEGACY(ECExplicitPrime2G);*/
 # ifndef OPENSSL_NO_EC2M
         ADD_TEST_SUITE(ECExplicitTriNamedCurve);
         ADD_TEST_SUITE_LEGACY(ECExplicitTriNamedCurve);
@@ -1427,7 +1427,7 @@ void cleanup_tests(void)
 {
 #ifndef OPENSSL_NO_EC
     OSSL_PARAM_free(ec_explicit_prime_params_nc);
-    OSSL_PARAM_free(ec_explicit_prime_params_explicit);
+/*    OSSL_PARAM_free(ec_explicit_prime_params_explicit);*/
     OSSL_PARAM_BLD_free(bld_prime_nc);
     OSSL_PARAM_BLD_free(bld_prime);
 # ifndef OPENSSL_NO_EC2M
@@ -1449,7 +1449,7 @@ void cleanup_tests(void)
 #ifndef OPENSSL_NO_EC
     FREE_DOMAIN_KEYS(EC);
     FREE_DOMAIN_KEYS(ECExplicitPrimeNamedCurve);
-    FREE_DOMAIN_KEYS(ECExplicitPrime2G);
+/*    FREE_DOMAIN_KEYS(ECExplicitPrime2G);*/
 # ifndef OPENSSL_NO_EC2M
     FREE_DOMAIN_KEYS(ECExplicitTriNamedCurve);
     FREE_DOMAIN_KEYS(ECExplicitTri2G);
diff -up openssl-3.0.1/test/recipes/30-test_evp_data/evppkey_ecdsa.txt.disable_explicit_ec openssl-3.0.1/test/recipes/30-test_evp_data/evppkey_ecdsa.txt
--- openssl-3.0.1/test/recipes/30-test_evp_data/evppkey_ecdsa.txt.disable_explicit_ec	2022-03-25 11:20:50.920949208 +0100
+++ openssl-3.0.1/test/recipes/30-test_evp_data/evppkey_ecdsa.txt	2022-03-25 11:21:13.177147598 +0100
@@ -121,18 +121,6 @@ AAAA//////////+85vqtpxeehPO5ysL8YyVRAgEB
 3ev1gTwRBduzqqlwd54AUSgI+pjttW8zrWNitO8H1sf59MPWOESKxNtZ1+Nl
 -----END PRIVATE KEY-----
 
-PrivateKey = EC_EXPLICIT
------BEGIN PRIVATE KEY-----
-MIIBeQIBADCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAAB
-AAAAAAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA
-///////////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMV
-AMSdNgiG5wSTamZ44ROdJreBn36QBEEE5JcIvn36opqjEm/k59Al40rBAxWM2TPG
-l0L13Je51zHpfXQ9Z2o7IQicMXP4wSfJ0qCgg2bgydqoxlYrlLGuVQIhAP////8A
-AAAA//////////+85vqtpxeehPO5ysL8YyVRAgEBBG0wawIBAQQgec92jwduadCk
-OjoNRI+YT5Be5TkzZXzYCyTLkMOikDmhRANCAATtECEhQbLEaiUj/Wu0qjcr81lL
-46dx5zYgArz/iaSNJ3W80oO+F7v04jlQ7wxQzg96R0bwKiMeq5CcW9ZFt6xg
------END PRIVATE KEY-----
-
 PrivateKey = B-163
 -----BEGIN PRIVATE KEY-----
 MGMCAQAwEAYHKoZIzj0CAQYFK4EEAA8ETDBKAgEBBBUDnQW0mLiHVha/jqFznX/K
