diff -rupN --no-dereference openssl-3.0.9/crypto/ec/ec_asn1.c openssl-3.0.9-new/crypto/ec/ec_asn1.c
--- openssl-3.0.9/crypto/ec/ec_asn1.c	2023-05-30 14:31:57.000000000 +0200
+++ openssl-3.0.9-new/crypto/ec/ec_asn1.c	2023-05-31 16:36:52.583276335 +0200
@@ -905,6 +905,12 @@ 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;
@@ -964,6 +970,11 @@ 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 -rupN --no-dereference openssl-3.0.9/test/endecode_test.c openssl-3.0.9-new/test/endecode_test.c
--- openssl-3.0.9/test/endecode_test.c	2023-05-30 14:31:57.000000000 +0200
+++ openssl-3.0.9-new/test/endecode_test.c	2023-05-31 16:36:52.583276335 +0200
@@ -58,7 +58,7 @@ 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;
@@ -1005,9 +1005,9 @@ 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)
@@ -1338,7 +1338,7 @@ 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())
@@ -1366,7 +1366,7 @@ 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);
@@ -1409,8 +1409,8 @@ 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);
@@ -1447,7 +1447,7 @@ 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
@@ -1469,7 +1469,7 @@ 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 -rupN --no-dereference openssl-3.0.9/test/recipes/30-test_evp_data/evppkey_ecdsa.txt openssl-3.0.9-new/test/recipes/30-test_evp_data/evppkey_ecdsa.txt
--- openssl-3.0.9/test/recipes/30-test_evp_data/evppkey_ecdsa.txt	2023-05-30 14:31:57.000000000 +0200
+++ openssl-3.0.9-new/test/recipes/30-test_evp_data/evppkey_ecdsa.txt	2023-05-31 16:36:52.583276335 +0200
@@ -133,18 +133,6 @@ 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