diff --git a/plugins/out_s3/s3.c b/plugins/out_s3/s3.c
index 8840f82821e..b4556158000 100644
--- a/plugins/out_s3/s3.c
+++ b/plugins/out_s3/s3.c
@@ -103,7 +103,7 @@ static char *mock_error_response(char *error_env_var)
 
     err_val = getenv(error_env_var);
     if (err_val != NULL && strlen(err_val) > 0) {
-        error = flb_malloc(strlen(err_val) + sizeof(char));
+        error = flb_calloc(strlen(err_val) + 1, sizeof(char));
         if (error == NULL) {
             flb_errno();
             return NULL;
@@ -156,7 +156,7 @@ int create_headers(struct flb_s3 *ctx, char *body_md5,
         return 0;
     }
 
-    s3_headers = flb_malloc(sizeof(struct flb_aws_header) * headers_len);
+    s3_headers = flb_calloc(headers_len, sizeof(struct flb_aws_header));
     if (s3_headers == NULL) {
         flb_errno();
         return -1;
@@ -241,7 +241,7 @@ struct flb_http_client *mock_s3_call(char *error_env_var, char *api)
                               "Server: AmazonS3";
             /* since etag is in the headers, this code uses resp.data */
             len = strlen(resp);
-            c->resp.data = flb_malloc(len + 1);
+            c->resp.data = flb_calloc(len + 1, sizeof(char));
             if (!c->resp.data) {
                 flb_errno();
                 return NULL;
@@ -1558,7 +1558,7 @@ static int add_to_queue(struct flb_s3 *ctx, struct s3_file *upload_file,
     flb_sds_t tag_cpy;
 
     /* Create upload contents object and add to upload queue */
-    upload_contents = flb_malloc(sizeof(struct upload_queue));
+    upload_contents = flb_calloc(1, sizeof(struct upload_queue));
     if (upload_contents == NULL) {
         flb_plg_error(ctx->ins, "Error allocating memory for upload_queue entry");
         flb_errno();
@@ -1888,7 +1888,7 @@ static flb_sds_t flb_pack_msgpack_extract_log_key(void *out_context, const char
     }
 
     /* Allocate buffer to store log_key contents */
-    val_buf = flb_malloc(msgpack_size);
+    val_buf = flb_calloc(1, msgpack_size);
     if (val_buf == NULL) {
         flb_plg_error(ctx->ins, "Could not allocate enough "
                       "memory to read record");
diff --git a/src/aws/flb_aws_util.c b/src/aws/flb_aws_util.c
index 61d09bf5a13..cc78c0cdeb4 100644
--- a/src/aws/flb_aws_util.c
+++ b/src/aws/flb_aws_util.c
@@ -94,7 +94,7 @@ char *flb_aws_endpoint(char* service, char* region)
     len += strlen(region);
     len++; /* null byte */
 
-    endpoint = flb_malloc(len);
+    endpoint = flb_calloc(len, sizeof(char));
     if (!endpoint) {
         flb_errno();
         return NULL;
@@ -136,7 +136,7 @@ int flb_read_file(const char *path, char **out_buf, size_t *out_size)
         return -1;
     }
 
-    buf = flb_malloc(st.st_size + sizeof(char));
+    buf = flb_calloc(st.st_size + 1, sizeof(char));
     if (!buf) {
         flb_errno();
         close(fd);
@@ -851,7 +851,7 @@ flb_sds_t flb_get_s3_key(const char *format, time_t time, const char *tag,
     /* Find all occurences of $INDEX and replace with the appropriate index. */
     if (strstr((char *) format, INDEX_STRING)) {
         seq_index_len = snprintf(NULL, 0, "%"PRIu64, seq_index);
-        seq_index_str = flb_malloc(seq_index_len + 1);
+        seq_index_str = flb_calloc(seq_index_len + 1, sizeof(char));
         if (seq_index_str == NULL) {
             goto error;
         }
@@ -859,7 +859,10 @@ flb_sds_t flb_get_s3_key(const char *format, time_t time, const char *tag,
         sprintf(seq_index_str, "%"PRIu64, seq_index);
         seq_index_str[seq_index_len] = '\0';
         tmp_key = replace_uri_tokens(s3_key, INDEX_STRING, seq_index_str);
-
+        if (tmp_key == NULL) {
+            flb_free(seq_index_str);
+            goto error;
+        }
         if (strlen(tmp_key) > S3_KEY_SIZE) {
             flb_warn("[s3_key] Object key length is longer than the 1024 character limit.");
         }
diff --git a/src/flb_config.c b/src/flb_config.c
index c6782ad3654..6ecfce81816 100644
--- a/src/flb_config.c
+++ b/src/flb_config.c
@@ -287,6 +287,11 @@ struct flb_config *flb_config_init()
 
     /* Environment */
     config->env = flb_env_create();
+    if (!config->env) {
+        flb_error("[config] environment creation failed");
+        flb_config_exit(config);
+        return NULL;
+    }
 
     /* Multiline core */
     mk_list_init(&config->multiline_parsers);
diff --git a/src/multiline/flb_ml_parser.c b/src/multiline/flb_ml_parser.c
index 2a672605691..441f9caf578 100644
--- a/src/multiline/flb_ml_parser.c
+++ b/src/multiline/flb_ml_parser.c
@@ -333,6 +333,11 @@ void flb_ml_parser_destroy_all(struct mk_list *list)
     struct mk_list *head;
     struct flb_ml_parser *parser;
 
+    /* Ensure list is initialized */
+    if (list->next == NULL) {
+        return;
+    }
+
     mk_list_foreach_safe(head, tmp, list) {
         parser = mk_list_entry(head, struct flb_ml_parser, _head);
         flb_ml_parser_destroy(parser);