diff --git a/openbsc/src/libmgcp/mgcp_osmux.c b/openbsc/src/libmgcp/mgcp_osmux.c
index be0db99..b46a80e 100644
--- a/openbsc/src/libmgcp/mgcp_osmux.c
+++ b/openbsc/src/libmgcp/mgcp_osmux.c
@@ -543,7 +543,7 @@
 }
 
 /* bsc-nat allocates/releases the Osmux circuit ID */
-static uint8_t osmux_cid_bitmap[16];
+static uint8_t osmux_cid_bitmap[(OSMUX_CID_MAX + 1) / 8];
 
 int osmux_used_cid(void)
 {
diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index ec86c55..6c94002 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -1186,7 +1186,7 @@
 	osmux_put_cid(id);
 	OSMO_ASSERT(osmux_used_cid() == 0);
 
-	for (i = 0; i < 128; ++i) {
+	for (i = 0; i < 256; ++i) {
 		id = osmux_get_cid();
 		OSMO_ASSERT(id == i);
 		OSMO_ASSERT(osmux_used_cid() == i + 1);