diff --git a/lib/libc/net/ascii2addr.c b/lib/libc/net/ascii2addr.c
index 27d62459052d..415d07de7861 100644
--- a/lib/libc/net/ascii2addr.c
+++ b/lib/libc/net/ascii2addr.c
@@ -51,7 +51,7 @@ ascii2addr(af, ascii, result)
 	switch(af) {
 	case AF_INET:
 		ina = result;
-		strncat(strbuf, ascii, (sizeof strbuf)-1);
+		strncpy(strbuf, ascii, (sizeof strbuf)-1);
 		if (inet_aton(strbuf, ina))
 			return sizeof(struct in_addr);
 		errno = EINVAL;