diff --git a/CHANGES b/CHANGES
index 03e6c64510..caafe97e27 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,9 @@
+1844.	[bug]		inet_pton() accepted more that 4 hexadecimal digits
+			for each 16 bit piece of the IPv6 address.  The text
+			representation of a IPv6 address has been tighted
+			to disallow this (draft-ietf-ipv6-addr-arch-v4-02.txt).
+			[RT #5662]
+
 1843.	[cleanup]	CINCLUDES takes precedence over CFLAGS.  This helps
 			when CFLAGS contains "-I /usr/local/include"
 			resulting in old header files being used.
diff --git a/lib/isc/inet_pton.c b/lib/isc/inet_pton.c
index 487f9e6bbe..71ec5fceef 100644
--- a/lib/isc/inet_pton.c
+++ b/lib/isc/inet_pton.c
@@ -17,7 +17,7 @@
 
 #if defined(LIBC_SCCS) && !defined(lint)
 static char rcsid[] =
-	"$Id: inet_pton.c,v 1.13 2004/03/05 05:10:46 marka Exp $";
+	"$Id: inet_pton.c,v 1.13.18.1 2005/03/31 07:26:45 marka Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <config.h>
@@ -132,7 +132,7 @@ inet_pton6(const char *src, unsigned char *dst) {
 			  xdigits_u[] = "0123456789ABCDEF";
 	unsigned char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 	const char *xdigits, *curtok;
-	int ch, saw_xdigit;
+	int ch, seen_xdigits;
 	unsigned int val;
 
 	memset((tp = tmp), '\0', NS_IN6ADDRSZ);
@@ -143,7 +143,7 @@ inet_pton6(const char *src, unsigned char *dst) {
 		if (*++src != ':')
 			return (0);
 	curtok = src;
-	saw_xdigit = 0;
+	seen_xdigits = 0;
 	val = 0;
 	while ((ch = *src++) != '\0') {
 		const char *pch;
@@ -153,14 +153,13 @@ inet_pton6(const char *src, unsigned char *dst) {
 		if (pch != NULL) {
 			val <<= 4;
 			val |= (pch - xdigits);
-			if (val > 0xffff)
+			if (++seen_xdigits > 4)
 				return (0);
-			saw_xdigit = 1;
 			continue;
 		}
 		if (ch == ':') {
 			curtok = src;
-			if (!saw_xdigit) {
+			if (!seen_xdigits) {
 				if (colonp)
 					return (0);
 				colonp = tp;
@@ -170,19 +169,19 @@ inet_pton6(const char *src, unsigned char *dst) {
 				return (0);
 			*tp++ = (unsigned char) (val >> 8) & 0xff;
 			*tp++ = (unsigned char) val & 0xff;
-			saw_xdigit = 0;
+			seen_xdigits = 0;
 			val = 0;
 			continue;
 		}
 		if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
 		    inet_pton4(curtok, tp) > 0) {
 			tp += NS_INADDRSZ;
-			saw_xdigit = 0;
+			seen_xdigits = 0;
 			break;	/* '\0' was seen by inet_pton4(). */
 		}
 		return (0);
 	}
-	if (saw_xdigit) {
+	if (seen_xdigits) {
 		if (tp + NS_INT16SZ > endp)
 			return (0);
 		*tp++ = (unsigned char) (val >> 8) & 0xff;
diff --git a/lib/lwres/lwinetpton.c b/lib/lwres/lwinetpton.c
index eae5d6c0ab..f7673cf4d5 100644
--- a/lib/lwres/lwinetpton.c
+++ b/lib/lwres/lwinetpton.c
@@ -16,7 +16,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$Id: lwinetpton.c,v 1.7 2004/03/05 05:12:46 marka Exp $";
+static char rcsid[] = "$Id: lwinetpton.c,v 1.7.18.1 2005/03/31 07:26:45 marka Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <config.h>
@@ -129,7 +129,7 @@ inet_pton6(const char *src, unsigned char *dst) {
 			  xdigits_u[] = "0123456789ABCDEF";
 	unsigned char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 	const char *xdigits, *curtok;
-	int ch, saw_xdigit;
+	int ch, seen_xdigits;
 	unsigned int val;
 
 	memset((tp = tmp), '\0', NS_IN6ADDRSZ);
@@ -140,7 +140,7 @@ inet_pton6(const char *src, unsigned char *dst) {
 		if (*++src != ':')
 			return (0);
 	curtok = src;
-	saw_xdigit = 0;
+	seen_xdigits = 0;
 	val = 0;
 	while ((ch = *src++) != '\0') {
 		const char *pch;
@@ -150,14 +150,13 @@ inet_pton6(const char *src, unsigned char *dst) {
 		if (pch != NULL) {
 			val <<= 4;
 			val |= (pch - xdigits);
-			if (val > 0xffff)
+			if (++seen_xdigits > 4)
 				return (0);
-			saw_xdigit = 1;
 			continue;
 		}
 		if (ch == ':') {
 			curtok = src;
-			if (!saw_xdigit) {
+			if (!seen_xdigits) {
 				if (colonp)
 					return (0);
 				colonp = tp;
@@ -167,19 +166,19 @@ inet_pton6(const char *src, unsigned char *dst) {
 				return (0);
 			*tp++ = (unsigned char) (val >> 8) & 0xff;
 			*tp++ = (unsigned char) val & 0xff;
-			saw_xdigit = 0;
+			seen_xdigits = 0;
 			val = 0;
 			continue;
 		}
 		if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
 		    inet_pton4(curtok, tp) > 0) {
 			tp += NS_INADDRSZ;
-			saw_xdigit = 0;
+			seen_xdigits = 0;
 			break;	/* '\0' was seen by inet_pton4(). */
 		}
 		return (0);
 	}
-	if (saw_xdigit) {
+	if (seen_xdigits) {
 		if (tp + NS_INT16SZ > endp)
 			return (0);
 		*tp++ = (unsigned char) (val >> 8) & 0xff;