diff --git a/lib/src/clixon_validate.c b/lib/src/clixon_validate.c
index 4e0c195b9..8fa38f036 100644
--- a/lib/src/clixon_validate.c
+++ b/lib/src/clixon_validate.c
@@ -181,7 +181,10 @@ validate_leafref_err(char      *xpath,
     cbuf *cbm = NULL;
     int   exist = 0;
     char *msg = NULL;
+    char *body;
 
+    if ((body = xml_body(xt)) == NULL)
+        body = "";
     if ((cbi = cbuf_new()) == NULL){
         clixon_err(OE_UNIX, errno, "cbuf_new");
         goto done;
@@ -195,12 +198,12 @@ validate_leafref_err(char      *xpath,
             goto done;
         }
         cprintf(cbm, "%s", msg);
-        cprintf(cbi, "%s", xml_body(xt));
+        cprintf(cbi, "%s", body);
     }
     else{
         if (validate_errmsg(&cbm, xt, yt) < 0)
             goto done;
-        cprintf(cbi, "<%s>%s</%s>", xml_name(xt), xml_body(xt), xml_name(xt));
+        cprintf(cbi, "<%s>%s</%s>", xml_name(xt), body, xml_name(xt));
     }
     if (xret && netconf_missing_yang_xml(xret, xpath, "instance-required",   cbuf_get(cbi), cbuf_get(cbm)) < 0)
         goto done;
@@ -631,8 +634,10 @@ validate_leafref(cxobj     *xt,
         clixon_err(OE_YANG, 0, "No argument for Y_PATH");
         goto done;
     }
+    /* Empty value is a value: it must also refer to an existing (empty) instance,
+     * see https://github.com/clicon/clixon/issues/647 */
     if ((leafrefbody = xml_body(xt)) == NULL)
-        goto ok;
+        leafrefbody = "";
     if (xml_nsctx_yang(yt, &nsc) < 0)
         goto done;
 #ifdef LEAFREF_OPTIMIZE
@@ -667,7 +672,8 @@ validate_leafref(cxobj     *xt,
                                       &leafref_opt.lc_bin_x0) < 0)
             goto done;
     }
-    if (leafref_opt.lc_bin_search){
+    /* Binary search requires a non-empty key, use linear search for empty value */
+    if (leafref_opt.lc_bin_search && *leafrefbody != '\0'){
         if ((ret = leafref_opt_search(xpath, xt, leafref_opt.lc_bin_x0, ytype, xret)) < 0)
             goto done;
         if (ret == 0)
@@ -679,7 +685,7 @@ validate_leafref(cxobj     *xt,
             for (i = 0; i < xlen; i++) {
                 x = xvec[i];
                 if ((leafbody = xml_body(x)) == NULL)
-                    continue;
+                    leafbody = "";
                 if (strcmp(leafbody, leafrefbody) == 0)
                     break;
             }
diff --git a/test/test_leafref_empty.sh b/test/test_leafref_empty.sh
new file mode 100755
index 000000000..5493e49f9
--- /dev/null
+++ b/test/test_leafref_empty.sh
@@ -0,0 +1,154 @@
+#!/usr/bin/env bash
+# Yang leafref with empty value
+# An empty value must refer to an existing instance with empty value, as any other value
+# See https://github.com/clicon/clixon/issues/647
+
+# Magic line must be first in script (see README.md)
+s="$_" ; . ./lib.sh || if [ "$s" = $0 ]; then exit 0; else return 0; fi
+
+APPNAME=example
+
+cfg=$dir/conf_yang.xml
+fyang=$dir/leafref.yang
+
+cat <<EOF > $cfg
+<clixon-config xmlns="http://clicon.org/config">
+  <CLICON_CONFIGFILE>$cfg</CLICON_CONFIGFILE>
+  <CLICON_YANG_DIR>$dir</CLICON_YANG_DIR>
+  <CLICON_YANG_DIR>${YANG_INSTALLDIR}</CLICON_YANG_DIR>
+  <CLICON_YANG_MAIN_FILE>$fyang</CLICON_YANG_MAIN_FILE>
+  <CLICON_CLISPEC_DIR>/usr/local/lib/$APPNAME/clispec</CLICON_CLISPEC_DIR>
+  <CLICON_CLI_DIR>/usr/local/lib/$APPNAME/cli</CLICON_CLI_DIR>
+  <CLICON_CLI_MODE>$APPNAME</CLICON_CLI_MODE>
+  <CLICON_SOCK>/usr/local/var/run/$APPNAME.sock</CLICON_SOCK>
+  <CLICON_BACKEND_PIDFILE>/usr/local/var/run/$APPNAME.pidfile</CLICON_BACKEND_PIDFILE>
+  <CLICON_XMLDB_DIR>/usr/local/var/$APPNAME</CLICON_XMLDB_DIR>
+</clixon-config>
+EOF
+
+cat <<EOF > $fyang
+module leafref{
+    yang-version 1.1;
+    namespace "urn:example:clixon";
+    prefix ex;
+    container groups {
+        leaf-list name {
+            type string;
+        }
+    }
+    list zone {
+        key name;
+        leaf name {
+            type string;
+        }
+        leaf label {
+            type string;
+        }
+    }
+    container test {
+        list object {
+            key id;
+            leaf id {
+                type string;
+            }
+            leaf group {
+                description "leafref to leaf-list";
+                type leafref {
+                    path "/ex:groups/ex:name";
+                }
+            }
+            leaf zone {
+                description "leafref to list key";
+                type leafref {
+                    path "/ex:zone/ex:name";
+                }
+            }
+            leaf label {
+                description "leafref to non-key list leaf";
+                type leafref {
+                    path "/ex:zone/ex:label";
+                }
+            }
+        }
+    }
+}
+EOF
+
+new "test params: -f $cfg"
+
+if [ $BE -ne 0 ]; then
+    new "kill old backend"
+    sudo clixon_backend -zf $cfg
+    if [ $? -ne 0 ]; then
+        err
+    fi
+    new "start backend  -s init -f $cfg"
+    start_backend -s init -f $cfg
+fi
+
+new "wait backend"
+wait_backend
+
+new "netconf set groups and zones"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><groups xmlns=\"urn:example:clixon\"><name>g1</name><name>g2</name></groups><zone xmlns=\"urn:example:clixon\"><name>z1</name><label>a</label></zone><zone xmlns=\"urn:example:clixon\"><name>z2</name><label>b</label></zone><zone xmlns=\"urn:example:clixon\"><name>z3</name><label>c</label></zone></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf commit groups and zones"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><commit/></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf set non-empty refs"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><test xmlns=\"urn:example:clixon\"><object><id>o1</id><group>g2</group><zone>z2</zone><label>c</label></object></test></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf validate non-empty refs ok"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><validate><source><candidate/></source></validate></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf discard-changes"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><discard-changes/></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf set empty leafref to leaf-list"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><test xmlns=\"urn:example:clixon\"><object><id>o1</id><group/></object></test></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf validate empty leafref to leaf-list not ok"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><validate><source><candidate/></source></validate></rpc>" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>data-missing</error-tag><error-app-tag>instance-required</error-app-tag><error-path>/ex:groups/ex:name</error-path><error-info><group/></error-info>" ""
+
+new "netconf discard-changes"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><discard-changes/></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf set empty leafref to list key"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><test xmlns=\"urn:example:clixon\"><object><id>o1</id><zone></zone></object></test></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf validate empty leafref to list key not ok"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><validate><source><candidate/></source></validate></rpc>" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>data-missing</error-tag><error-app-tag>instance-required</error-app-tag><error-path>/ex:zone/ex:name</error-path><error-info><zone/></error-info>" ""
+
+new "netconf discard-changes"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><discard-changes/></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf set empty leafref to non-key leaf"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><test xmlns=\"urn:example:clixon\"><object><id>o1</id><label/></object></test></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf validate empty leafref to non-key leaf not ok"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><validate><source><candidate/></source></validate></rpc>" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>data-missing</error-tag><error-app-tag>instance-required</error-app-tag><error-path>/ex:zone/ex:label</error-path><error-info><label/></error-info>" ""
+
+new "netconf set referred non-key leaf to empty value"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><zone xmlns=\"urn:example:clixon\"><name>z3</name><label/></zone></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf validate empty leafref to existing empty value ok"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><validate><source><candidate/></source></validate></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "netconf discard-changes"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><discard-changes/></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+if [ $BE -ne 0 ]; then
+    new "Kill backend"
+    # Check if premature kill
+    pid=$(pgrep -u root -f clixon_backend)
+    if [ -z "$pid" ]; then
+        err "backend already dead"
+    fi
+    # kill backend
+    stop_backend -f $cfg
+fi
+
+rm -rf $dir
+
+new "endtest"
+endtest