diff --git a/src/CKHashTable.c b/src/CKHashTable.c
index bf826dc0..0014ec63 100644
--- a/src/CKHashTable.c
+++ b/src/CKHashTable.c
@@ -227,11 +227,20 @@ int ck_str_n_hash_insert(const char *key, size_t keylen, const void *value, ck_h
         ck_hash_entry_t *entry = &table->entries[hash_key];
         char *this_key = &table->keys[entry->key_offset];
         if (entry->key_length == 0) {
-            table->count++;
-            while (table->keys_used + keylen > table->keys_capacity) {
-                table->keys_capacity *= 2;
-                table->keys = realloc(table->keys, table->keys_capacity);
+            if (table->keys_used + keylen > table->keys_capacity) {
+                size_t new_capacity = table->keys_capacity;
+                while (table->keys_used + keylen > new_capacity) {
+                    if (new_capacity > SIZE_MAX / 2)
+                        return 0;
+                    new_capacity *= 2;
+                }
+                char *new_keys = realloc(table->keys, new_capacity);
+                if (new_keys == NULL)
+                    return 0;
+                table->keys = new_keys;
+                table->keys_capacity = new_capacity;
             }
+            table->count++;
             memcpy(table->keys + table->keys_used, key, keylen);
             entry->key_offset = table->keys_used;
             entry->key_length = keylen;
diff --git a/src/sas/readstat_sas7bcat_read.c b/src/sas/readstat_sas7bcat_read.c
index 1d9c08eb..bd863aeb 100644
--- a/src/sas/readstat_sas7bcat_read.c
+++ b/src/sas/readstat_sas7bcat_read.c
@@ -163,7 +163,12 @@ static readstat_error_t sas7bcat_parse_value_labels(const char *value_start, siz
             label_len = value_start + value_labels_len - &lbp2[10];
         }
         if (ctx->value_label_handler && !is_default_label) {
-            label = realloc(label, 4 * label_len + 1);
+            char *new_label = realloc(label, 4 * label_len + 1);
+            if (new_label == NULL) {
+                retval = READSTAT_ERROR_MALLOC;
+                goto cleanup;
+            }
+            label = new_label;
             retval = readstat_convert(label, 4 * label_len + 1,
                     &lbp2[10], label_len, ctx->converter);
             if (retval != READSTAT_OK)
diff --git a/src/spss/readstat_sav_write.c b/src/spss/readstat_sav_write.c
index 61c5c7a1..795d67d7 100644
--- a/src/spss/readstat_sav_write.c
+++ b/src/spss/readstat_sav_write.c
@@ -993,7 +993,12 @@ static readstat_error_t sav_emit_long_string_value_labels_record(readstat_writer
             if (storage_width <= 8)
                 continue;
 
-            space_buffer = realloc(space_buffer, user_width);
+            char *new_space_buffer = realloc(space_buffer, user_width);
+            if (new_space_buffer == NULL) {
+                retval = READSTAT_ERROR_MALLOC;
+                goto cleanup;
+            }
+            space_buffer = new_space_buffer;
             memset(space_buffer, ' ', user_width);
 
             retval = readstat_write_bytes(writer, &name_len, sizeof(int32_t));
diff --git a/src/txt/readstat_txt_read.c b/src/txt/readstat_txt_read.c
index e48f687a..4ecd81ae 100644
--- a/src/txt/readstat_txt_read.c
+++ b/src/txt/readstat_txt_read.c
@@ -58,7 +58,14 @@ static ssize_t txt_getdelim(char ** restrict linep, size_t * restrict linecapp,
     ssize_t bytes_read = 0;
     while ((bytes_read = io->read(&value_buffer[i], 1, io->io_ctx)) == 1 && value_buffer[i++] != delimiter) {
         if (i == value_buffer_len) {
-            value_buffer = realloc(value_buffer, value_buffer_len *= 2);
+            char *new_value_buffer = realloc(value_buffer, value_buffer_len * 2);
+            if (new_value_buffer == NULL) {
+                *linep = value_buffer;
+                *linecapp = value_buffer_len;
+                return -2;
+            }
+            value_buffer = new_value_buffer;
+            value_buffer_len *= 2;
         }
     }
     *linep = value_buffer;
@@ -91,6 +98,10 @@ static readstat_error_t txt_parse_delimited(readstat_parser_t *parser,
                 retval = READSTAT_ERROR_READ;
                 goto cleanup;
             }
+            if (chars_read == -2) {
+                retval = READSTAT_ERROR_MALLOC;
+                goto cleanup;
+            }
             if (parser->handlers.value && !entry->skip) {
                 chars_read--; // delimiter
                 if (chars_read > 0 && value_buffer[chars_read-1] == '\r') {