diff --git a/ChangeLog b/ChangeLog
index 09f1a0a03..48b1cfc4f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2004-04-14 18:20  Alexander Malmberg <alexander@malmberg.org>
+
+	* Source/Additions/Unicode.m (GSToUnicode): In an utf8 sequence,
+	check the the continuation bytes are valid continuation bytes.
+
 2004-04-13 Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Tools/GNUmakefile:
diff --git a/Source/Additions/Unicode.m b/Source/Additions/Unicode.m
index db8223327..cf72a851d 100644
--- a/Source/Additions/Unicode.m
+++ b/Source/Additions/Unicode.m
@@ -1211,8 +1211,15 @@ GSToUnicode(unichar **dst, unsigned int *size, const unsigned char *src,
 		  /* get the codepoint */
 		  for (i = 1; i < sle; i++)
 		    {
+		      if (src[spos + i] < 0x80 || src[spos + i] >= 0xc0)
+			break;
 		      u = (u << 6) | (src[spos + i] & 0x3f);
 		    }
+		  if (i < sle)
+		    {
+		      result = NO;
+		      break;
+		    }
 	          u = u & ~(0xffffffff << ((5 * sle) + 1));
 		  spos += sle;
                 }
@@ -1270,7 +1277,7 @@ GSToUnicode(unichar **dst, unsigned int *size, const unsigned char *src,
       case NSNonLossyASCIIStringEncoding:
       case NSASCIIStringEncoding:
       case NSISOLatin1StringEncoding:
-      case NSUnicodeStringEncoding: 	  
+      case NSUnicodeStringEncoding:
 	while (spos < slen)
 	  {
 	    if (dpos >= bsize)
@@ -1835,7 +1842,7 @@ GSFromUnicode(unsigned char **dst, unsigned int *size, const unichar *src,
 	goto bases;
 
       case NSISOLatin1StringEncoding:
-      case NSUnicodeStringEncoding: 	  
+      case NSUnicodeStringEncoding:
 	base = 256;
 	goto bases;