diff --git a/apps/app_fax.c b/apps/app_fax.c
index ede2044373..a5afe87dde 100644
--- a/apps/app_fax.c
+++ b/apps/app_fax.c
@@ -559,6 +559,7 @@ static int transmit_audio(fax_session *s)
 		}
 
 		ast_frfree(inf);
+		inf = NULL;
 	}
 
 	ast_debug(1, "Loop finished, res=%d\n", res);
@@ -698,6 +699,7 @@ static int transmit_t38(fax_session *s)
 		}
 
 		ast_frfree(inf);
+		inf = NULL;
 	}
 
 	ast_debug(1, "Loop finished, res=%d\n", res);