diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index f87a4c6..ceef2d8 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -971,8 +971,12 @@
 	}
 
 	if (rc) {
-		msc_subscr_conn_close(conn, GSM_CAUSE_AUTH_FAILED);
-		return -EINVAL;
+		LOGP(DMM, LOGL_ERROR,
+		     "%s: MM AUTHENTICATION RESPONSE: invalid: parsing %s AKA Auth Response"
+		     " failed with rc=%d; dispatching zero length SRES/RES to trigger failure\n",
+		     vlr_subscr_name(conn->vsub), is_r99 ? "UMTS" : "GSM", rc);
+		memset(res, 0, sizeof(res));
+		res_len = 0;
 	}
 
 	DEBUGP(DMM, "%s: MM %s AUTHENTICATION RESPONSE (%s = %s)\n",
diff --git a/tests/msc_vlr/msc_vlr_test_gsm_authen.c b/tests/msc_vlr/msc_vlr_test_gsm_authen.c
index 9c09aa4..b0db12d 100644
--- a/tests/msc_vlr/msc_vlr_test_gsm_authen.c
+++ b/tests/msc_vlr/msc_vlr_test_gsm_authen.c
@@ -914,11 +914,70 @@
 	comment_end();
 }
 
+static void test_wrong_sres_length()
+{
+	comment_start();
+	fake_time_start();
+
+	net->authentication_required = true;
+
+	btw("Location Update request causes a GSUP Send Auth Info request to HLR");
+	lu_result_sent = RES_NONE;
+	gsup_expect_tx("08010809710000004026f0");
+	ms_sends_msg("050802008168000130089910070000006402");
+	OSMO_ASSERT(gsup_tx_confirmed);
+	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
+
+	btw("from HLR, rx _SEND_AUTH_INFO_RESULT; VLR sends Auth Req to MS");
+	auth_request_sent = false;
+	auth_request_expect_rand = "585df1ae287f6e273dce07090d61320b";
+	auth_request_expect_autn = NULL;
+	/* Based on a Ki of 000102030405060708090a0b0c0d0e0f */
+	gsup_rx("0a"
+		/* imsi */
+		"0108" "09710000004026f0"
+		/* 5 auth vectors... */
+		/* TL    TL     rand */
+		"0322"  "2010" "585df1ae287f6e273dce07090d61320b"
+		/*       TL     sres       TL     kc */
+			"2104" "2d8b2c3e" "2208" "61855fb81fc2a800"
+		"0322"  "2010" "12aca96fb4ffdea5c985cbafa9b6e18b"
+			"2104" "20bde240" "2208" "07fa7502e07e1c00"
+		"0322"  "2010" "e7c03ba7cf0e2fde82b2dc4d63077d42"
+			"2104" "a29514ae" "2208" "e2b234f807886400"
+		"0322"  "2010" "fa8f20b781b5881329d4fea26b1a3c51"
+			"2104" "5afc8d72" "2208" "2392f14f709ae000"
+		"0322"  "2010" "0fd4cc8dbe8715d1f439e304edfd68dc"
+			"2104" "bc8d1c5b" "2208" "da7cdd6bfe2d7000",
+		NULL);
+	VERBOSE_ASSERT(auth_request_sent, == true, "%d");
+	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
+
+	btw("If the HLR were to send a GSUP _UPDATE_LOCATION_RESULT we'd still reject");
+	gsup_rx("06010809710000004026f0", NULL);
+	EXPECT_ACCEPTED(false);
+
+	thwart_rx_non_initial_requests();
+
+	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
+
+	btw("MS sends Authen Response with too short SRES data, auth is thwarted.");
+	gsup_expect_tx("0b010809710000004026f0"); /* OSMO_GSUP_MSGT_AUTH_FAIL_REPORT */
+	expect_bssap_clear();
+	ms_sends_msg("05542d8b2c");
+	VERBOSE_ASSERT(lu_result_sent, == RES_REJECT, "%d");
+
+	EXPECT_CONN_COUNT(0);
+	clear_vlr();
+	comment_end();
+}
+
 msc_vlr_test_func_t msc_vlr_tests[] = {
 	test_gsm_authen,
 	test_gsm_authen_tmsi,
 	test_gsm_authen_imei,
 	test_gsm_authen_tmsi_imei,
 	test_gsm_milenage_authen,
+	test_wrong_sres_length,
 	NULL
 };
diff --git a/tests/msc_vlr/msc_vlr_test_gsm_authen.err b/tests/msc_vlr/msc_vlr_test_gsm_authen.err
index a46a838..a454e2f 100644
--- a/tests/msc_vlr/msc_vlr_test_gsm_authen.err
+++ b/tests/msc_vlr/msc_vlr_test_gsm_authen.err
@@ -1998,6 +1998,120 @@
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
 talloc_total_blocks(tall_bsc_ctx) == 7
 
+===== test_wrong_sres_length
+- Total time passed: 0.000000 s
+- Location Update request causes a GSUP Send Auth Info request to HLR
+  MSC <--RAN_GERAN_A-- MS: GSM48_MT_MM_LOC_UPD_REQUEST
+  new conn
+DREF unknown: MSC conn use + compl_l3 == 1 (0x1)
+DRLL Dispatching 04.08 message GSM48_MT_MM_LOC_UPD_REQUEST (0x5:0x8)
+DREF unknown: MSC conn use + fsm == 2 (0x5)
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_INIT}: Allocated
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_INIT}: Received Event SUBSCR_CONN_E_START
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_INIT}: state_chg to SUBSCR_CONN_S_NEW
+DMM LOCATION UPDATING REQUEST: MI(IMSI)=901700000004620 type=IMSI ATTACH
+DMM LU/new-LAC: 1/23
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_IDLE}: Allocated
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_IDLE}: is child of Subscr_Conn(901700000004620)
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_IDLE}: rev=GSM net=GERAN Auth (no Ciph)
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_IDLE}: Received Event VLR_ULA_E_UPDATE_LA
+DREF VLR subscr unknown usage increases to: 1
+DVLR set IMSI on subscriber; IMSI=901700000004620 id=901700000004620
+DVLR New subscr, IMSI: 901700000004620
+DREF VLR subscr IMSI:901700000004620 usage increases to: 2
+DREF VLR subscr IMSI:901700000004620 usage decreases to: 1
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_IDLE}: vlr_loc_upd_node1()
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_IDLE}: state_chg to VLR_ULA_S_WAIT_AUTH
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_NEEDS_AUTH}: Allocated
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_NEEDS_AUTH}: is child of vlr_lu_fsm(901700000004620)
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_NEEDS_AUTH}: Received Event VLR_AUTH_E_START
+DVLR GSUP tx: 08010809710000004026f0
+GSUP --> HLR: OSMO_GSUP_MSGT_SEND_AUTH_INFO_REQUEST: 08010809710000004026f0
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_NEEDS_AUTH}: state_chg to VLR_SUB_AS_NEEDS_AUTH_WAIT_AI
+DMM IMSI:901700000004620: bump: conn still being established (SUBSCR_CONN_S_NEW)
+DREF IMSI:901700000004620: MSC conn use - compl_l3 == 1 (0x4)
+  lu_result_sent == 0
+- from HLR, rx _SEND_AUTH_INFO_RESULT; VLR sends Auth Req to MS
+<-- GSUP rx OSMO_GSUP_MSGT_SEND_AUTH_INFO_RESULT: 0a010809710000004026f003222010585df1ae287f6e273dce07090d61320b21042d8b2c3e220861855fb81fc2a8000322201012aca96fb4ffdea5c985cbafa9b6e18b210420bde240220807fa7502e07e1c0003222010e7c03ba7cf0e2fde82b2dc4d63077d422104a29514ae2208e2b234f80788640003222010fa8f20b781b5881329d4fea26b1a3c5121045afc8d7222082392f14f709ae000032220100fd4cc8dbe8715d1f439e304edfd68dc2104bc8d1c5b2208da7cdd6bfe2d7000
+DVLR GSUP rx 191: 0a010809710000004026f003222010585df1ae287f6e273dce07090d61320b21042d8b2c3e220861855fb81fc2a8000322201012aca96fb4ffdea5c985cbafa9b6e18b210420bde240220807fa7502e07e1c0003222010e7c03ba7cf0e2fde82b2dc4d63077d422104a29514ae2208e2b234f80788640003222010fa8f20b781b5881329d4fea26b1a3c5121045afc8d7222082392f14f709ae000032220100fd4cc8dbe8715d1f439e304edfd68dc2104bc8d1c5b2208da7cdd6bfe2d7000
+DREF VLR subscr IMSI:901700000004620 usage increases to: 2
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_NEEDS_AUTH_WAIT_AI}: Received Event VLR_AUTH_E_HLR_SAI_ACK
+DVLR SUBSCR(IMSI:901700000004620) Received 5 auth tuples
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_NEEDS_AUTH_WAIT_AI}: state_chg to VLR_SUB_AS_WAIT_RESP
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_WAIT_RESP}: got auth tuple: use_count=1 key_seq=0
+- sending GSM Auth Request for IMSI:901700000004620: tuple use_count=1 key_seq=0 auth_types=0x1 and...
+- ...rand=585df1ae287f6e273dce07090d61320b
+- ...expecting sres=2d8b2c3e
+DREF VLR subscr IMSI:901700000004620 usage decreases to: 1
+<-- GSUP rx OSMO_GSUP_MSGT_SEND_AUTH_INFO_RESULT: vlr_gsupc_read_cb() returns 0
+  auth_request_sent == 1
+  lu_result_sent == 0
+- If the HLR were to send a GSUP _UPDATE_LOCATION_RESULT we'd still reject
+<-- GSUP rx OSMO_GSUP_MSGT_UPDATE_LOCATION_RESULT: 06010809710000004026f0
+DVLR GSUP rx 11: 06010809710000004026f0
+DREF VLR subscr IMSI:901700000004620 usage increases to: 2
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_WAIT_AUTH}: Received Event VLR_ULA_E_HLR_LU_RES
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_WAIT_AUTH}: Event VLR_ULA_E_HLR_LU_RES not permitted
+DREF VLR subscr IMSI:901700000004620 usage decreases to: 1
+<-- GSUP rx OSMO_GSUP_MSGT_UPDATE_LOCATION_RESULT: vlr_gsupc_read_cb() returns 0
+msc_subscr_conn_is_accepted() == false
+  requests shall be thwarted
+DRLL Dispatching 04.08 message GSM48_MT_CC_SETUP (0x3:0x5)
+DRLL subscr IMSI:901700000004620: Message not permitted for initial conn: GSM48_MT_CC_SETUP
+DRLL Dispatching 04.08 message unknown 0x33 (0x5:0x33)
+DRLL subscr IMSI:901700000004620: Message not permitted for initial conn: unknown 0x33
+DRLL Dispatching 04.08 message GSM48_MT_RR_SYSINFO_1 (0x6:0x19)
+DRLL subscr IMSI:901700000004620: Message not permitted for initial conn: GSM48_MT_RR_SYSINFO_1
+DRLL Dispatching 04.08 message SMS:0x01 (0x9:0x1)
+DRLL subscr IMSI:901700000004620: Message not permitted for initial conn: SMS:0x01
+  lu_result_sent == 0
+- MS sends Authen Response with too short SRES data, auth is thwarted.
+  MSC <--RAN_GERAN_A-- MS: GSM48_MT_MM_AUTH_RESP
+DREF IMSI:901700000004620: MSC conn use + dtap == 2 (0x6)
+DRLL Dispatching 04.08 message GSM48_MT_MM_AUTH_RESP (0x5:0x14)
+DMM IMSI:901700000004620: MM AUTHENTICATION RESPONSE: l3 length invalid: 5
+DMM IMSI:901700000004620: MM AUTHENTICATION RESPONSE: invalid: parsing GSM AKA Auth Response failed with rc=-22; dispatching zero length SRES/RES to trigger failure
+DMM IMSI:901700000004620: MM GSM AUTHENTICATION RESPONSE (sres = )
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_WAIT_RESP}: Received Event VLR_AUTH_E_MS_AUTH_RESP
+DVLR SUBSCR(IMSI:901700000004620) received res: 
+DVLR SUBSCR(IMSI:901700000004620) AUTH RES missing or too short (0)
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_WAIT_RESP}: Authentication terminating with result VLR_AUTH_RES_AUTH_FAILED
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_WAIT_RESP}: state_chg to VLR_SUB_AS_AUTH_FAILED
+DVLR GSUP tx: 0b010809710000004026f0
+GSUP --> HLR: OSMO_GSUP_MSGT_AUTH_FAIL_REPORT: 0b010809710000004026f0
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_AUTH_FAILED}: Terminating (cause = OSMO_FSM_TERM_REGULAR)
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_AUTH_FAILED}: Removing from parent vlr_lu_fsm(901700000004620)
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_AUTH_FAILED}: Freeing instance
+DVLR VLR_Authenticate(901700000004620){VLR_SUB_AS_AUTH_FAILED}: Deallocated
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_WAIT_AUTH}: Received Event VLR_ULA_E_AUTH_RES
+- sending LU Reject for IMSI:901700000004620, cause 3
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_WAIT_AUTH}: state_chg to VLR_ULA_S_DONE
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_NEW}: Received Event SUBSCR_CONN_E_CN_CLOSE
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_NEW}: SUBSCR_CONN_FROM_LU
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_NEW}: Close event, cause 1
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_NEW}: state_chg to SUBSCR_CONN_S_RELEASED
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_RELEASED}: Terminating (cause = OSMO_FSM_TERM_REGULAR)
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_DONE}: Terminating (cause = OSMO_FSM_TERM_PARENT)
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_DONE}: Removing from parent Subscr_Conn(901700000004620)
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_DONE}: fsm_lu_cleanup called with cause OSMO_FSM_TERM_PARENT
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_DONE}: Freeing instance
+DVLR vlr_lu_fsm(901700000004620){VLR_ULA_S_DONE}: Deallocated
+DMM msc_subscr_conn_close(vsub=IMSI:901700000004620, cause=2): no conn fsm, releasing directly without release event.
+- BSSAP Clear --RAN_GERAN_A--> MS
+DREF IMSI:901700000004620: MSC conn use - fsm == 1 (0x2)
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_RELEASED}: Freeing instance
+DMM Subscr_Conn(901700000004620){SUBSCR_CONN_S_RELEASED}: Deallocated
+DREF IMSI:901700000004620: MSC conn use - dtap == 0 (0x0)
+DRLL subscr IMSI:901700000004620: Freeing subscriber connection
+DREF VLR subscr IMSI:901700000004620 usage decreases to: 0
+DREF freeing VLR subscr IMSI:901700000004620
+  lu_result_sent == 2
+  llist_count(&net->subscr_conns) == 0
+===== test_wrong_sres_length: SUCCESS
+
+full talloc report on 'msgb' (total      0 bytes in   1 blocks)
+talloc_total_blocks(tall_bsc_ctx) == 7
+
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
 talloc_total_blocks(tall_bsc_ctx) == 7