diff --git a/src/org/joni/ByteCodeMachine.java b/src/org/joni/ByteCodeMachine.java
index a6a0cddc..1514d08b 100644
--- a/src/org/joni/ByteCodeMachine.java
+++ b/src/org/joni/ByteCodeMachine.java
@@ -1060,7 +1060,7 @@ private void opWordBound() {
         if (s == str) {
             if (s >= range || !enc.isMbcWord(bytes, s, end)) {opFail(); return;}
         } else if (s == end) {
-            if (!enc.isMbcWord(bytes, sprev, end)) {opFail(); return;}
+            if (s >= range || !enc.isMbcWord(bytes, sprev, end)) {opFail(); return;}
         } else {
             if (enc.isMbcWord(bytes, s, end) == enc.isMbcWord(bytes, sprev, end)) {opFail(); return;}
         }
@@ -1080,7 +1080,7 @@ private void opNotWordBound() {
         if (s == str) {
             if (s < range && enc.isMbcWord(bytes, s, end)) {opFail(); return;}
         } else if (s == end) {
-            if (enc.isMbcWord(bytes, sprev, end)) {opFail(); return;}
+            if (sprev < end && enc.isMbcWord(bytes, sprev, end)) {opFail(); return;}
         } else {
             if (enc.isMbcWord(bytes, s, end) != enc.isMbcWord(bytes, sprev, end)) {opFail(); return;}
         }