diff --git a/src/org/joni/ByteCodeMachine.java b/src/org/joni/ByteCodeMachine.java
index db4d6a2e..9056166e 100644
--- a/src/org/joni/ByteCodeMachine.java
+++ b/src/org/joni/ByteCodeMachine.java
@@ -526,7 +526,7 @@ private void opExactMB2N3() {
 
     private void opExactMB2N() {
         int tlen = code[ip++];
-        if (tlen * 2 > range) {opFail(); return;}
+        if (s + tlen * 2 > range) {opFail(); return;}
 
         if (Config.USE_STRING_TEMPLATES) {
             byte[]bs = regex.templates[code[ip++]];
@@ -551,7 +551,7 @@ private void opExactMB2N() {
 
     private void opExactMB3N() {
         int tlen = code[ip++];
-        if (tlen * 3 > range) {opFail(); return;}
+        if (s + tlen * 3 > range) {opFail(); return;}
 
         if (Config.USE_STRING_TEMPLATES) {
             byte[]bs = regex.templates[code[ip++]];
diff --git a/test/org/joni/test/TestU8.java b/test/org/joni/test/TestU8.java
index a3f0767f..53400f69 100644
--- a/test/org/joni/test/TestU8.java
+++ b/test/org/joni/test/TestU8.java
@@ -75,6 +75,7 @@ public void test() {
         // x2s(pat2, str2, 4, 4);
         // x2s(pat2, str2, 4, 4, Option.IGNORECASE);
 
+        ns("(?i-mx:ak)a", "ema");
     }
 
     public static void main(String[] args) throws Throwable {