diff --git a/source/lib/util_sid.c b/source/lib/util_sid.c

index 032be9a..2c5a0c7 100644

--- a/source/lib/util_sid.c

+++ b/source/lib/util_sid.c

@@ -403,6 +403,9 @@ BOOL sid_parse(const char *inbuf, size_t len, DOM_SID *sid)

 	sid->sid_rev_num = CVAL(inbuf, 0);

 	sid->num_auths = CVAL(inbuf, 1);

+	if (sid->num_auths > MAXSUBAUTHS) {

+		return false;

+	}

 	memcpy(sid->id_auth, inbuf+2, 6);

 	if (len < 8 + sid->num_auths*4)

 		return False;

diff --git a/source/libads/ldap.c b/source/libads/ldap.c

index 7479894..eebc0fd 100644

--- a/source/libads/ldap.c

+++ b/source/libads/ldap.c

@@ -1771,7 +1771,9 @@ static void dump_sid(const char *field, struct berval **values)

 	int i;

 	for (i=0; values[i]; i++) {

 		DOM_SID sid;

-		sid_parse(values[i]->bv_val, values[i]->bv_len, &sid);

+		if (!sid_parse(values[i]->bv_val, values[i]->bv_len, &sid)) {

+			return;

+		}

 		printf("%s: %s\n", field, sid_string_static(&sid));

 	}

 }

diff --git a/source/libsmb/cliquota.c b/source/libsmb/cliquota.c

index 2a47ae2..5721b67 100644

--- a/source/libsmb/cliquota.c

+++ b/source/libsmb/cliquota.c

@@ -117,7 +117,9 @@ static BOOL parse_user_quota_record(const char *rdata, unsigned int rdata_count,

 	}

 #endif /* LARGE_SMB_OFF_T */

-	sid_parse(rdata+40,sid_len,&qt.sid);

+	if (!sid_parse(rdata+40,sid_len,&qt.sid)) {

+		return False;

+	}

 	qt.qtype = SMB_USER_QUOTA_TYPE;

diff --git a/source/smbd/nttrans.c b/source/smbd/nttrans.c

index 2b9d5da..60bab7e 100644

--- a/source/smbd/nttrans.c

+++ b/source/smbd/nttrans.c

@@ -2424,7 +2424,10 @@ static int call_nt_transact_ioctl(connection_struct *conn, char *inbuf, char *ou

 		/* unknown 4 bytes: this is not the length of the sid :-(  */

 		/*unknown = IVAL(pdata,0);*/

-		sid_parse(pdata+4,sid_len,&sid);

+		if (!sid_parse(pdata+4,sid_len,&sid)) {

+			return ERROR_NT(NT_STATUS_INVALID_PARAMETER);

+		}

+

 		DEBUGADD(10,("for SID: %s\n",sid_string_static(&sid)));

 		if (!sid_to_uid(&sid, &uid)) {

@@ -2662,7 +2665,9 @@ static int call_nt_transact_get_user_quota(connection_struct *conn, char *inbuf,

 				break;

 			}

-			sid_parse(pdata+8,sid_len,&sid);

+			if (!sid_parse(pdata+8,sid_len,&sid)) {

+				return ERROR_NT(NT_STATUS_INVALID_PARAMETER);

+			}

 			if (vfs_get_ntquota(fsp, SMB_USER_QUOTA_TYPE, &sid, &qt)!=0) {

 				ZERO_STRUCT(qt);

@@ -2828,7 +2833,9 @@ static int call_nt_transact_set_user_quota(connection_struct *conn, char *inbuf,

 	}

 #endif /* LARGE_SMB_OFF_T */

-	sid_parse(pdata+40,sid_len,&sid);

+	if (!sid_parse(pdata+40,sid_len,&sid)) {

+		return ERROR_NT(NT_STATUS_INVALID_PARAMETER);

+	}

 	DEBUGADD(8,("SID: %s\n",sid_string_static(&sid)));

 	/* 44 unknown bytes left... */