diff --git a/format.c b/format.c
index 69e25e0..e300fe7 100644
--- a/format.c
+++ b/format.c
@@ -368,6 +368,7 @@ static void write_sam_cigar(kstring_t *s, int sam_flag, int in_tag, int qlen, co
 			if (clip_len[1]) mm_sprintf_lite(s, ",%u", clip_len[1]<<4|clip_char);
 		} else {
 			int clip_char = (sam_flag&0x800) && !(opt_flag&MM_F_SOFTCLIP)? 'H' : 'S';
+			assert(clip_len[0] < qlen && clip_len[1] < qlen);
 			if (clip_len[0]) mm_sprintf_lite(s, "%d%c", clip_len[0], clip_char);
 			for (k = 0; k < r->p->n_cigar; ++k)
 				mm_sprintf_lite(s, "%d%c", r->p->cigar[k]>>4, "MIDNSHP=XB"[r->p->cigar[k]&0xf]);
diff --git a/main.c b/main.c
index 02373a7..19359f6 100644
--- a/main.c
+++ b/main.c
@@ -6,7 +6,7 @@
 #include "mmpriv.h"
 #include "ketopt.h"
 
-#define MM_VERSION "2.15-r906-dirty"
+#define MM_VERSION "2.15-r908-dirty"
 
 #ifdef __linux__
 #include <sys/resource.h>