diff --git a/src/drv_maildir.c b/src/drv_maildir.c
index e751f4b..cb2d268 100644
--- a/src/drv_maildir.c
+++ b/src/drv_maildir.c
@@ -496,7 +496,7 @@ maildir_uidval_lock( maildir_store_t *ctx )
 		return DRV_BOX_BAD;
 	}
 	lseek( ctx->uvfd, 0, SEEK_SET );
-	if ((n = read( ctx->uvfd, buf, sizeof(buf) )) <= 0 ||
+	if ((n = read( ctx->uvfd, buf, sizeof(buf) - 1 )) <= 0 ||
 	    (buf[n] = 0, sscanf( buf, "%d\n%d", &ctx->gen.uidvalidity, &ctx->nuid ) != 2)) {
 #if 1
 		/* In a generic driver, resetting the UID validity would be the right thing.
diff --git a/src/mdconvert.c b/src/mdconvert.c
index da9970f..ec2a558 100644
--- a/src/mdconvert.c
+++ b/src/mdconvert.c
@@ -135,7 +135,7 @@ convert( const char *box, int altmap )
 	key.data = (void *)"UIDVALIDITY";
 	key.size = 11;
 	if (altmap) {
-		if ((n = read( sfd, buf, sizeof(buf) )) <= 0 ||
+		if ((n = read( sfd, buf, sizeof(buf) - 1 )) <= 0 ||
 		    (buf[n] = 0, sscanf( buf, "%d\n%d", &uv[0], &uv[1] ) != 2))
 		{
 			fprintf( stderr, "Error: cannot read UIDVALIDITY of '%s'.\n", box );