diff --git a/libavcodec/tests/rangecoder.c b/libavcodec/tests/rangecoder.c
index 2da5c0ce33..3a8ba6759c 100644
--- a/libavcodec/tests/rangecoder.c
+++ b/libavcodec/tests/rangecoder.c
@@ -29,7 +29,7 @@
 int main(void)
 {
     RangeCoder c;
-    uint8_t b[9 * SIZE];
+    uint8_t b[9 * SIZE] = {0};
     uint8_t r[9 * SIZE];
     int i;
     uint8_t state[10];