diff --git a/appl/su/su.c b/appl/su/su.c
index 531bcdb61..488fd099c 100644
--- a/appl/su/su.c
+++ b/appl/su/su.c
@@ -303,7 +303,7 @@ verify_unix(struct passwd *login, struct passwd *su)
 	if(r != 0)
 	    exit(0);
 	pw = crypt(pw_buf, su->pw_passwd);
-	memset(pw_buf, 0, sizeof(pw_buf));
+	memset_s(pw_buf, sizeof(pw_buf), 0, sizeof(pw_buf));
 	if(strcmp(pw, su->pw_passwd) != 0) {
 	    syslog (LOG_ERR | LOG_AUTH, "%s to %s: incorrect password",
 		    login->pw_name, su->pw_name);
diff --git a/kadmin/cpw.c b/kadmin/cpw.c
index 425575d89..28cd30b52 100644
--- a/kadmin/cpw.c
+++ b/kadmin/cpw.c
@@ -76,7 +76,7 @@ set_random_password (krb5_principal principal, int keepold)
 	printf ("%s's password set to \"%s\"\n", princ_name, pw);
 	free (princ_name);
     }
-    memset (pw, 0, sizeof(pw));
+    memset_s(pw, sizeof(pw), 0, sizeof(pw));
     return ret;
 }
 
@@ -108,7 +108,7 @@ set_password (krb5_principal principal, char *password, int keepold)
     if(ret == 0)
 	ret = kadm5_chpass_principal_3(kadm_handle, principal, keepold, 0, NULL,
 				       password);
-    memset(pwbuf, 0, sizeof(pwbuf));
+    memset_s(pwbuf, sizeof(pwbuf), 0, sizeof(pwbuf));
     return ret;
 }
 
diff --git a/kadmin/random_password.c b/kadmin/random_password.c
index 970e99d34..93e5d761c 100644
--- a/kadmin/random_password.c
+++ b/kadmin/random_password.c
@@ -68,7 +68,7 @@ random_password(char *pw, size_t len)
 		      "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 2,
 		      "@$%&*()-+=:,/<>1234567890", 1);
     strlcpy(pw, pass, len);
-    memset(pass, 0, strlen(pass));
+    memset_s(pass, sizeof(pass), 0, strlen(pass));
     free(pass);
 #endif
 }
@@ -155,7 +155,7 @@ generate_password(char **pw, int num_classes, ...)
 	}
     }
     (*pw)[len] = '\0';
-    memset(rbuf, 0, sizeof(rbuf));
+    memset_s(rbuf, sizeof(rbuf), 0, sizeof(rbuf));
     free(classes);
 }
 #endif
diff --git a/kuser/kinit.c b/kuser/kinit.c
index 174c4fe3c..dcb86bcf1 100644
--- a/kuser/kinit.c
+++ b/kuser/kinit.c
@@ -677,7 +677,7 @@ get_new_tickets(krb5_context context,
     if (ntlm_domain && passwd[0])
 	heim_ntlm_nt_key(passwd, &ntlmkey);
 #endif
-    memset(passwd, 0, sizeof(passwd));
+    memset_s(passwd, sizeof(passwd), 0, sizeof(passwd));
 
     switch(ret){
     case 0:
diff --git a/lib/gssapi/krb5/arcfour.c b/lib/gssapi/krb5/arcfour.c
index 0aa2da080..d88ec4cdd 100644
--- a/lib/gssapi/krb5/arcfour.c
+++ b/lib/gssapi/krb5/arcfour.c
@@ -304,7 +304,7 @@ _gssapi_get_mic_arcfour(OM_uint32 * minor_status,
     EVP_Cipher(&rc4_key, p, p, 8);
     EVP_CIPHER_CTX_cleanup(&rc4_key);
 
-    memset(k6_data, 0, sizeof(k6_data));
+    memset_s(k6_data, sizeof(k6_data), 0, sizeof(k6_data));
 
     *minor_status = 0;
     return GSS_S_COMPLETE;
@@ -389,7 +389,7 @@ _gssapi_verify_mic_arcfour(OM_uint32 * minor_status,
     else
 	cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
 
-    memset(SND_SEQ, 0, sizeof(SND_SEQ));
+    memset_s(SND_SEQ, sizeof(SND_SEQ), 0, sizeof(SND_SEQ));
     if (cmp != 0) {
 	*minor_status = 0;
 	return GSS_S_BAD_MIC;
@@ -516,7 +516,7 @@ _gssapi_wrap_arcfour(OM_uint32 * minor_status,
     ret = arcfour_mic_key(context, &Klocal,
 			  p0 + 8, 4, /* SND_SEQ */
 			  k6_data, sizeof(k6_data));
-    memset(Klocaldata, 0, sizeof(Klocaldata));
+    memset_s(Klocaldata, sizeof(Klocaldata), 0, sizeof(Klocaldata));
     if (ret) {
 	_gsskrb5_release_buffer(minor_status, output_message_buffer);
 	*minor_status = ret;
@@ -550,7 +550,7 @@ _gssapi_wrap_arcfour(OM_uint32 * minor_status,
 	EVP_CipherInit_ex(&rc4_key, EVP_rc4(), NULL, k6_data, NULL, 1);
 	EVP_Cipher(&rc4_key, p0 + 8, p0 + 8 /* SND_SEQ */, 8);
 	EVP_CIPHER_CTX_cleanup(&rc4_key);
-	memset(k6_data, 0, sizeof(k6_data));
+	memset_s(k6_data, sizeof(k6_data), 0, sizeof(k6_data));
     }
 
     if (conf_state)
@@ -650,7 +650,7 @@ OM_uint32 _gssapi_unwrap_arcfour(OM_uint32 *minor_status,
 	EVP_CipherInit_ex(&rc4_key, EVP_rc4(), NULL, k6_data, NULL, 1);
 	EVP_Cipher(&rc4_key, SND_SEQ, p0 + 8, 8);
 	EVP_CIPHER_CTX_cleanup(&rc4_key);
-	memset(k6_data, 0, sizeof(k6_data));
+	memset_s(k6_data, sizeof(k6_data), 0, sizeof(k6_data));
     }
 
     _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number);
@@ -678,7 +678,7 @@ OM_uint32 _gssapi_unwrap_arcfour(OM_uint32 *minor_status,
     ret = arcfour_mic_key(context, &Klocal,
 			  SND_SEQ, 4,
 			  k6_data, sizeof(k6_data));
-    memset(Klocaldata, 0, sizeof(Klocaldata));
+    memset_s(Klocaldata, sizeof(Klocaldata), 0, sizeof(Klocaldata));
     if (ret) {
 	*minor_status = ret;
 	return GSS_S_FAILURE;
@@ -1069,7 +1069,7 @@ _gssapi_wrap_iov_arcfour(OM_uint32 *minor_status,
     kret = arcfour_mic_key(context, &Klocal,
 			   p0 + 8, 4, /* SND_SEQ */
 			   k6_data, sizeof(k6_data));
-    memset(Klocaldata, 0, sizeof(Klocaldata));
+    memset_s(Klocaldata, sizeof(Klocaldata), 0, sizeof(Klocaldata));
     if (kret) {
 	*minor_status = kret;
 	major_status = GSS_S_FAILURE;
@@ -1300,7 +1300,7 @@ _gssapi_unwrap_iov_arcfour(OM_uint32 *minor_status,
 			   snd_seq,
 			   4,
 			   k6_data, sizeof(k6_data));
-    memset(Klocaldata, 0, sizeof(Klocaldata));
+    memset_s(Klocaldata, sizeof(Klocaldata), 0, sizeof(Klocaldata));
     if (kret) {
 	*minor_status = kret;
 	return GSS_S_FAILURE;
diff --git a/lib/gssapi/krb5/get_mic.c b/lib/gssapi/krb5/get_mic.c
index 643385d9e..d9cf9d700 100644
--- a/lib/gssapi/krb5/get_mic.c
+++ b/lib/gssapi/krb5/get_mic.c
@@ -121,8 +121,8 @@ mic_des
 			       ++seq_number);
   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 
-  memset (deskey, 0, sizeof(deskey));
-  memset (&schedule, 0, sizeof(schedule));
+  memset_s(deskey, sizeof(deskey), 0, sizeof(deskey));
+  memset_s(&schedule, sizeof(schedule), 0, sizeof(schedule));
 
   *minor_status = 0;
   return GSS_S_COMPLETE;
diff --git a/lib/gssapi/krb5/verify_mic.c b/lib/gssapi/krb5/verify_mic.c
index 9968ce403..7070f3de4 100644
--- a/lib/gssapi/krb5/verify_mic.c
+++ b/lib/gssapi/krb5/verify_mic.c
@@ -89,8 +89,8 @@ verify_mic_des
   DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
 		 &schedule, &zero);
   if (ct_memcmp (p - 8, hash, 8) != 0) {
-    memset (deskey, 0, sizeof(deskey));
-    memset (&schedule, 0, sizeof(schedule));
+    memset_s(deskey, sizeof(deskey), 0, sizeof(deskey));
+    memset_s(&schedule, sizeof(schedule), 0, sizeof(schedule));
     return GSS_S_BAD_MIC;
   }
 
@@ -105,8 +105,8 @@ verify_mic_des
   EVP_Cipher(&des_ctx, p, p, 8);
   EVP_CIPHER_CTX_cleanup(&des_ctx);
 
-  memset (deskey, 0, sizeof(deskey));
-  memset (&schedule, 0, sizeof(schedule));
+  memset_s(deskey, sizeof(deskey), 0, sizeof(deskey));
+  memset_s(&schedule, sizeof(schedule), 0, sizeof(schedule));
 
   seq = p;
   _gsskrb5_decode_om_uint32(seq, &seq_number);
diff --git a/lib/gssapi/ntlm/init_sec_context.c b/lib/gssapi/ntlm/init_sec_context.c
index 27530328f..53a07dd80 100644
--- a/lib/gssapi/ntlm/init_sec_context.c
+++ b/lib/gssapi/ntlm/init_sec_context.c
@@ -72,11 +72,11 @@ from_file(const char *fn, const char *target_domain,
 
 	heim_ntlm_nt_key(p, key);
 
-	memset(buf, 0, sizeof(buf));
+	memset_s(buf, sizeof(buf), 0, sizeof(buf));
 	fclose(f);
 	return 0;
     }
-    memset(buf, 0, sizeof(buf));
+    memset_s(buf, sizeof(buf), 0, sizeof(buf));
     fclose(f);
     return ENOENT;
 }
@@ -463,7 +463,7 @@ _gss_ntlm_init_sec_context
 	    ret = heim_ntlm_build_ntlm1_master(ntlmv2, sizeof(ntlmv2),
 					       &sessionkey,
 					       &type3.sessionkey);
-	    memset(ntlmv2, 0, sizeof(ntlmv2));
+	    memset_s(ntlmv2, sizeof(ntlmv2), 0, sizeof(ntlmv2));
 	    if (ret) {
 		_gss_ntlm_delete_sec_context(minor_status,
 					     context_handle, NULL);
diff --git a/lib/hcrypto/md2.c b/lib/hcrypto/md2.c
index 25341a93b..da41e6d83 100644
--- a/lib/hcrypto/md2.c
+++ b/lib/hcrypto/md2.c
@@ -90,7 +90,7 @@ calc(struct md2 *m, const void *v)
     }
 
     memcpy(m->state, x, 16);
-    memset(x, 0, sizeof(x));
+    memset_s(x, sizeof(x), 0, sizeof(x));
 }
 
 int
diff --git a/lib/hcrypto/rand-fortuna.c b/lib/hcrypto/rand-fortuna.c
index 529bf8f30..2082f35ec 100644
--- a/lib/hcrypto/rand-fortuna.c
+++ b/lib/hcrypto/rand-fortuna.c
@@ -159,7 +159,7 @@ md_result(MD_CTX * ctx, unsigned char *dst)
 
     memcpy(&tmp, ctx, sizeof(*ctx));
     SHA256_Final(dst, &tmp);
-    memset(&tmp, 0, sizeof(tmp));
+    memset_s(&tmp, sizeof(tmp), 0, sizeof(tmp));
 }
 
 /*
@@ -234,7 +234,7 @@ enough_time_passed(FState * st)
     if (ok)
 	memcpy(last, &tv, sizeof(tv));
 
-    memset(&tv, 0, sizeof(tv));
+    memset_s(&tv, sizeof(tv), 0, sizeof(tv));
 
     return ok;
 }
@@ -284,8 +284,8 @@ reseed(FState * st)
     /* use new key */
     ciph_init(&st->ciph, st->key, BLOCK);
 
-    memset(&key_md, 0, sizeof(key_md));
-    memset(buf, 0, BLOCK);
+    memset_s(&key_md, sizeof(key_md), 0, sizeof(key_md));
+    memset_s(buf, sizeof(buf), 0, sizeof(buf));
 }
 
 /*
@@ -335,8 +335,8 @@ add_entropy(FState * st, const unsigned char *data, unsigned len)
     if (pos == 0)
 	st->pool0_bytes += len;
 
-    memset(hash, 0, BLOCK);
-    memset(&md, 0, sizeof(md));
+    memset_s(hash, sizeof(hash), 0, sizeof(hash));
+    memset_s(&md, sizeof(hash), 0, sizeof(md));
 }
 
 /*
@@ -372,7 +372,7 @@ startup_tricks(FState * st)
 	encrypt_counter(st, buf + CIPH_BLOCK);
 	md_update(&st->pool[i], buf, BLOCK);
     }
-    memset(buf, 0, BLOCK);
+    memset_s(buf, sizeof(buf), 0, sizeof(buf));
 
     /* Hide the key. */
     rekey(st);
@@ -468,7 +468,7 @@ fortuna_reseed(void)
 	if ((*hc_rand_unix_method.bytes)(buf, sizeof(buf)) == 1) {
 	    add_entropy(&main_state, buf, sizeof(buf));
 	    entropy_p = 1;
-	    memset(buf, 0, sizeof(buf));
+	    memset_s(buf, sizeof(buf), 0, sizeof(buf));
 	}
     }
 #endif
@@ -509,7 +509,7 @@ fortuna_reseed(void)
 	    close(fd);
 	}
 
-	memset(&u, 0, sizeof(u));
+	memset_s(&u, sizeof(u), 0, sizeof(u));
 
 	entropy_p = 1; /* sure about this ? */
     }
@@ -593,7 +593,7 @@ fortuna_cleanup(void)
 
     init_done = 0;
     have_entropy = 0;
-    memset(&main_state, 0, sizeof(main_state));
+    memset_s(&main_state, sizeof(main_state), 0, sizeof(main_state));
 
     HEIMDAL_MUTEX_unlock(&fortuna_mutex);
 }
diff --git a/lib/hdb/mkey.c b/lib/hdb/mkey.c
index 8265776bf..cfc27d424 100644
--- a/lib/hdb/mkey.c
+++ b/lib/hdb/mkey.c
@@ -226,7 +226,7 @@ read_master_encryptionkey(krb5_context context, const char *filename,
     }
 
     ret = decode_EncryptionKey(buf, len, &key, &ret_len);
-    memset(buf, 0, sizeof(buf));
+    memset_s(buf, sizeof(buf), 0, sizeof(buf));
     if(ret)
 	return ret;
 
@@ -279,7 +279,7 @@ read_master_krb4(krb5_context context, const char *filename,
     memset(&key, 0, sizeof(key));
     key.keytype = ETYPE_DES_PCBC_NONE;
     ret = krb5_data_copy(&key.keyvalue, buf, len);
-    memset(buf, 0, sizeof(buf));
+    memset_s(buf, sizeof(buf), 0, sizeof(buf));
     if(ret)
 	return ret;
 
diff --git a/lib/hx509/ks_file.c b/lib/hx509/ks_file.c
index 642dd173b..d7726f084 100644
--- a/lib/hx509/ks_file.c
+++ b/lib/hx509/ks_file.c
@@ -126,10 +126,10 @@ try_decrypt(hx509_context context,
 					   &clear,
 					   NULL);
 
-    memset(clear.data, 0, clear.length);
+    memset_s(clear.data, clear.length, 0, clear.length);
     free(clear.data);
 out:
-    memset(key, 0, keylen);
+    memset_s(key, keylen, 0, keylen);
     free(key);
     return ret;
 }
@@ -292,7 +292,7 @@ parse_pem_private_key(hx509_context context, const char *fn,
 		ret = try_decrypt(context, c, ai, cipher, ivdata, password,
 				  strlen(password), data, len);
 	    /* XXX add password to lock password collection ? */
-	    memset(password, 0, sizeof(password));
+	    memset_s(password, sizeof(password), 0, sizeof(password));
 	}
 	free(ivdata);
 
diff --git a/lib/krb5/crypto-arcfour.c b/lib/krb5/crypto-arcfour.c
index e195bd3a0..ae576eccf 100644
--- a/lib/krb5/crypto-arcfour.c
+++ b/lib/krb5/crypto-arcfour.c
@@ -180,9 +180,9 @@ ARCFOUR_subencrypt(krb5_context context,
     EVP_Cipher(&ctx, cdata + 16, cdata + 16, len - 16);
     EVP_CIPHER_CTX_cleanup(&ctx);
 
-    memset (k1_c_data, 0, sizeof(k1_c_data));
-    memset (k2_c_data, 0, sizeof(k2_c_data));
-    memset (k3_c_data, 0, sizeof(k3_c_data));
+    memset_s(k1_c_data, sizeof(k1_c_data), 0, sizeof(k1_c_data));
+    memset_s(k2_c_data, sizeof(k2_c_data), 0, sizeof(k2_c_data));
+    memset_s(k3_c_data, sizeof(k3_c_data), 0, sizeof(k3_c_data));
     return 0;
 }
 
@@ -247,9 +247,9 @@ ARCFOUR_subdecrypt(krb5_context context,
     if (ret)
 	krb5_abortx(context, "hmac failed");
 
-    memset (k1_c_data, 0, sizeof(k1_c_data));
-    memset (k2_c_data, 0, sizeof(k2_c_data));
-    memset (k3_c_data, 0, sizeof(k3_c_data));
+    memset_s(k1_c_data, sizeof(k1_c_data), 0, sizeof(k1_c_data));
+    memset_s(k2_c_data, sizeof(k2_c_data), 0, sizeof(k2_c_data));
+    memset_s(k3_c_data, sizeof(k3_c_data), 0, sizeof(k3_c_data));
 
     if (ct_memcmp (cksum.checksum.data, data, 16) != 0) {
 	krb5_clear_error_message (context);
diff --git a/lib/krb5/crypto-des-common.c b/lib/krb5/crypto-des-common.c
index 2565914de..95f6389d1 100644
--- a/lib/krb5/crypto-des-common.c
+++ b/lib/krb5/crypto-des-common.c
@@ -77,7 +77,7 @@ _krb5_des_checksum(krb5_context context,
     EVP_DigestUpdate(m, data, len);
     EVP_DigestFinal_ex (m, p + 8, NULL);
     EVP_MD_CTX_destroy(m);
-    memset (&ivec, 0, sizeof(ivec));
+    memset_s(&ivec, sizeof(ivec), 0, sizeof(ivec));
     EVP_CipherInit_ex(&ctx->ectx, NULL, NULL, NULL, (void *)&ivec, -1);
     EVP_Cipher(&ctx->ectx, p, p, 24);
 
@@ -103,7 +103,7 @@ _krb5_des_verify(krb5_context context,
     if (m == NULL)
 	return krb5_enomem(context);
 
-    memset(&ivec, 0, sizeof(ivec));
+    memset_s(&ivec, sizeof(ivec), 0, sizeof(ivec));
     EVP_CipherInit_ex(&ctx->dctx, NULL, NULL, NULL, (void *)&ivec, -1);
     EVP_Cipher(&ctx->dctx, tmp, C->checksum.data, 24);
 
@@ -116,8 +116,8 @@ _krb5_des_verify(krb5_context context,
 	krb5_clear_error_message (context);
 	ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
     }
-    memset(tmp, 0, sizeof(tmp));
-    memset(res, 0, sizeof(res));
+    memset_s(tmp, sizeof(tmp), 0, sizeof(tmp));
+    memset_s(res, sizeof(res), 0, sizeof(res));
     return ret;
 }
 
diff --git a/lib/krb5/crypto-pk.c b/lib/krb5/crypto-pk.c
index c5d87a1b5..24a07cdbd 100644
--- a/lib/krb5/crypto-pk.c
+++ b/lib/krb5/crypto-pk.c
@@ -92,12 +92,12 @@ _krb5_pk_octetstring2key(krb5_context context,
 	offset += sizeof(shaoutput);
 	counter++;
     } while(offset < keylen);
-    memset(shaoutput, 0, sizeof(shaoutput));
+    memset_s(shaoutput, sizeof(shaoutput), 0, sizeof(shaoutput));
 
     EVP_MD_CTX_destroy(m);
 
     ret = krb5_random_to_key(context, type, keydata, keylen, key);
-    memset(keydata, 0, sizeof(keylen));
+    memset_s(keydata, sizeof(keylen), 0, sizeof(keylen));
     free(keydata);
     return ret;
 }
@@ -282,13 +282,13 @@ _krb5_pk_kdf(krb5_context context,
 	offset += EVP_MD_CTX_size(m);
 	counter++;
     } while(offset < keylen);
-    memset(shaoutput, 0, sizeof(shaoutput));
+    memset_s(shaoutput, sizeof(shaoutput), 0, sizeof(shaoutput));
 
     EVP_MD_CTX_destroy(m);
     free(other.data);
 
     ret = krb5_random_to_key(context, enctype, keydata, keylen, key);
-    memset(keydata, 0, sizeof(keylen));
+    memset_s(keydata, sizeof(keylen), 0, sizeof(keylen));
     free(keydata);
 
     return ret;
diff --git a/lib/krb5/deprecated.c b/lib/krb5/deprecated.c
index e3c142d88..5530e841b 100644
--- a/lib/krb5/deprecated.c
+++ b/lib/krb5/deprecated.c
@@ -207,7 +207,7 @@ krb5_password_key_proc (krb5_context context,
 	password = buf;
     }
     ret = krb5_string_to_key_salt (context, type, password, salt, *key);
-    memset (buf, 0, sizeof(buf));
+    memset_s(buf, sizeof(buf), 0, sizeof(buf));
     return ret;
 }
 
diff --git a/lib/krb5/init_creds_pw.c b/lib/krb5/init_creds_pw.c
index 1eece1760..e1dacc25f 100644
--- a/lib/krb5/init_creds_pw.c
+++ b/lib/krb5/init_creds_pw.c
@@ -162,7 +162,9 @@ free_init_creds_ctx(krb5_context context, krb5_init_creds_context ctx)
     if (ctx->keytab_data)
 	free(ctx->keytab_data);
     if (ctx->password) {
-	memset(ctx->password, 0, strlen(ctx->password));
+	size_t len;
+	len = strlen(ctx->password);
+	memset_s(ctx->password, len, 0, len);
 	free(ctx->password);
     }
     /*
@@ -189,7 +191,7 @@ free_init_creds_ctx(krb5_context context, krb5_init_creds_context ctx)
 	free_paid(context, ctx->ppaid);
 	free(ctx->ppaid);
     }
-    memset(ctx, 0, sizeof(*ctx));
+    memset_s(ctx, sizeof(*ctx), 0, sizeof(*ctx));
 }
 
 static int
@@ -629,8 +631,8 @@ change_password (krb5_context context,
     }
 
 out:
-    memset (buf1, 0, sizeof(buf1));
-    memset (buf2, 0, sizeof(buf2));
+    memset_s(buf1, sizeof(buf1), 0, sizeof(buf1));
+    memset_s(buf2, sizeof(buf2), 0, sizeof(buf2));
     krb5_data_free (&result_string);
     krb5_data_free (&result_code_string);
     krb5_free_cred_contents (context, &cpw_cred);
@@ -756,7 +758,7 @@ init_as_req (krb5_context context,
     return 0;
  fail:
     free_AS_REQ(a);
-    memset(a, 0, sizeof(*a));
+    memset_s(a, sizeof(*a), 0, sizeof(*a));
     return ret;
 }
 
@@ -1501,7 +1503,9 @@ krb5_init_creds_set_password(krb5_context context,
 			     const char *password)
 {
     if (ctx->password) {
-	memset(ctx->password, 0, strlen(ctx->password));
+	size_t len;
+	len = strlen(ctx->password);
+	memset_s(ctx->password, len, 0, len);
 	free(ctx->password);
     }
     if (password) {
@@ -2317,7 +2321,7 @@ krb5_init_creds_step(krb5_context context,
 	    if (ret == KRB5KDC_ERR_PREAUTH_REQUIRED) {
 
 	        free_METHOD_DATA(&ctx->md);
-	        memset(&ctx->md, 0, sizeof(ctx->md));
+		memset_s(&ctx->md, sizeof(ctx->md), 0, sizeof(ctx->md));
 
 		if (ctx->error.e_data) {
 		    ret = decode_METHOD_DATA(ctx->error.e_data->data,
@@ -2371,7 +2375,7 @@ krb5_init_creds_step(krb5_context context,
 		}
 
 		free_AS_REQ(&ctx->as_req);
-		memset(&ctx->as_req, 0, sizeof(ctx->as_req));
+		memset_s(&ctx->as_req, sizeof(ctx->as_req), 0, sizeof(ctx->as_req));
 
 		ctx->used_pa_types = 0;
 	    } else if (ret == KRB5KDC_ERR_KEY_EXP && ctx->runflags.change_password == 0 && ctx->prompter) {
@@ -2685,7 +2689,7 @@ krb5_get_init_creds_password(krb5_context context,
 	ret = (*prompter) (context, data, NULL, NULL, 1, &prompt);
 	free (q);
 	if (ret) {
-	    memset (buf, 0, sizeof(buf));
+	    memset_s(buf, sizeof(buf), 0, sizeof(buf));
 	    ret = KRB5_LIBOS_PWDINTR;
 	    krb5_clear_error_message (context);
 	    goto out;
@@ -2741,8 +2745,8 @@ krb5_get_init_creds_password(krb5_context context,
     if (ctx)
 	krb5_init_creds_free(context, ctx);
 
-    memset(buf, 0, sizeof(buf));
-    memset(buf2, 0, sizeof(buf2));
+    memset_s(buf, sizeof(buf), 0, sizeof(buf));
+    memset_s(buf2, sizeof(buf), 0, sizeof(buf2));
     return ret;
 }
 
diff --git a/lib/krb5/kcm.c b/lib/krb5/kcm.c
index 557dc5fe4..8e1dfff2d 100644
--- a/lib/krb5/kcm.c
+++ b/lib/krb5/kcm.c
@@ -224,7 +224,7 @@ kcm_free(krb5_context context, krb5_ccache *id)
     if (k != NULL) {
 	if (k->name != NULL)
 	    free(k->name);
-	memset(k, 0, sizeof(*k));
+	memset_s(k, sizeof(*k), 0, sizeof(*k));
 	krb5_data_free(&(*id)->data);
     }
 }
diff --git a/lib/krb5/salt-des.c b/lib/krb5/salt-des.c
index afcff675b..d898d6c20 100644
--- a/lib/krb5/salt-des.c
+++ b/lib/krb5/salt-des.c
@@ -109,7 +109,7 @@ krb5_DES_AFS3_Transarc_string_to_key (krb5_data pw,
     memset(&schedule, 0, sizeof(schedule));
     memset(&temp_key, 0, sizeof(temp_key));
     memset(&ivec, 0, sizeof(ivec));
-    memset(password, 0, sizeof(password));
+    memset_s(password, sizeof(password), 0, sizeof(password));
 
     DES_set_odd_parity (key);
 }
diff --git a/lib/krb5/salt-des3.c b/lib/krb5/salt-des3.c
index 342bba0d0..c4d2d7556 100644
--- a/lib/krb5/salt-des3.c
+++ b/lib/krb5/salt-des3.c
@@ -61,7 +61,7 @@ DES3_string_to_key(krb5_context context,
 
 	ret = _krb5_n_fold(str, len, tmp, 24);
 	if (ret) {
-	    memset(str, 0, len);
+	    memset_s(str, len, 0, len);
 	    free(str);
 	    krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
 	    return ret;
@@ -74,24 +74,24 @@ DES3_string_to_key(krb5_context context,
 		_krb5_xor8(*(keys + i), (const unsigned char*)"\0\0\0\0\0\0\0\xf0");
 	    DES_set_key_unchecked(keys + i, &s[i]);
 	}
-	memset(&ivec, 0, sizeof(ivec));
+	memset_s(&ivec, sizeof(ivec), 0, sizeof(ivec));
 	DES_ede3_cbc_encrypt(tmp,
 			     tmp, sizeof(tmp),
 			     &s[0], &s[1], &s[2], &ivec, DES_ENCRYPT);
-	memset(s, 0, sizeof(s));
-	memset(&ivec, 0, sizeof(ivec));
+	memset_s(s, sizeof(s), 0, sizeof(s));
+	memset_s(&ivec, sizeof(ivec), 0, sizeof(ivec));
 	for(i = 0; i < 3; i++){
 	    memcpy(keys + i, tmp + i * 8, sizeof(keys[i]));
 	    DES_set_odd_parity(keys + i);
 	    if(DES_is_weak_key(keys + i))
 		_krb5_xor8(*(keys + i), (const unsigned char*)"\0\0\0\0\0\0\0\xf0");
 	}
-	memset(tmp, 0, sizeof(tmp));
+	memset_s(tmp, sizeof(tmp), 0, sizeof(tmp));
     }
     key->keytype = enctype;
     krb5_data_copy(&key->keyvalue, keys, sizeof(keys));
-    memset(keys, 0, sizeof(keys));
-    memset(str, 0, len);
+    memset_s(keys, sizeof(keys), 0, sizeof(keys));
+    memset_s(str, sizeof(str), 0, len);
     free(str);
     return 0;
 }
@@ -119,7 +119,7 @@ DES3_string_to_key_derived(krb5_context context,
 				     len,
 				     enctype,
 				     key);
-    memset(s, 0, len);
+    memset_s(s, len, 0, len);
     free(s);
     return ret;
 }
diff --git a/lib/ntlm/ntlm.c b/lib/ntlm/ntlm.c
index 7ec0181ff..42dd09bed 100644
--- a/lib/ntlm/ntlm.c
+++ b/lib/ntlm/ntlm.c
@@ -1192,7 +1192,7 @@ splitandenc(unsigned char *hash,
     EVP_CipherInit_ex(&ctx, EVP_des_cbc(), NULL, key, NULL, 1);
     EVP_Cipher(&ctx, answer, challenge, 8);
     EVP_CIPHER_CTX_cleanup(&ctx);
-    memset(key, 0, sizeof(key));
+    memset_s(key, sizeof(key), 0, sizeof(key));
 }
 
 /**