diff --git a/locale/programs/linereader.c b/locale/programs/linereader.c
index 17099af744..f8c49ac06f 100644
--- a/locale/programs/linereader.c
+++ b/locale/programs/linereader.c
@@ -701,7 +701,7 @@ static bool
 utf8_sequence_error (struct linereader *lr, uint8_t ch1, int ch2, int ch3,
 		     int ch4)
 {
-  char buf[30];
+  char buf[38];
 
   if (ch2 < 0)
     snprintf (buf, sizeof (buf), "0x%02x", ch1);