diff --git a/host/lib/include/host_misc.h b/host/lib/include/host_misc.h
index 9759d44..0249420 100644
--- a/host/lib/include/host_misc.h
+++ b/host/lib/include/host_misc.h
@@ -44,6 +44,7 @@
 
 /**
  * Read data from a file into a newly allocated buffer.
+ * The buffer will end with an extra null byte ('\0', not counted in size).
  *
  * @param filename	Name of file to read from
  * @param data_ptr	On exit, pointer to newly allocated buffer with data
diff --git a/host/lib21/host_misc.c b/host/lib21/host_misc.c
index ebc4eac..6c0e0ef 100644
--- a/host/lib21/host_misc.c
+++ b/host/lib21/host_misc.c
@@ -42,11 +42,12 @@
 		return VB2_ERROR_READ_FILE_SIZE;
 	}
 
-	buf = malloc(size);
+	buf = malloc(size + 1);
 	if (!buf) {
 		fclose(f);
 		return VB2_ERROR_READ_FILE_ALLOC;
 	}
+	buf[size] = '\0';
 
 	if(1 != fread(buf, size, 1, f)) {
 		VB2_DEBUG("Unable to read file %s\n", filename);