R_API RConfigNode* r_config_set(RConfig *cfg, const char *name, const char *value) {
	RConfigNode *node = NULL;
	char *ov = NULL;
	ut64 oi;
	if (!cfg || STRNULL (name)) {
		return NULL;
	}
	node = r_config_node_get (cfg, name);
	if (node) {
		if (node->flags & CN_RO) {
			eprintf ("(error: '%s' config key is read only)\n", name);
			return node;
		}
		oi = node->i_value;
		if (node->value) {
			ov = strdup (node->value);
			if (!ov) {
				goto beach;
			}
		} else {
			free (node->value);
			node->value = strdup ("");
		}
		if (node->flags & CN_BOOL) {
			bool b = is_true (value);
			node->i_value = (ut64) b? 1: 0;
			char *value = strdup (r_str_bool (b));
			if (value) {
				free (node->value);
				node->value = value;
			}
		} else {
			if (!value) {
				free (node->value);
				node->value = strdup ("");
				node->i_value = 0;
			} else {
 				if (node->value == value) {
 					goto beach;
 				}
				char *tmp = node->value;
 				node->value = strdup (value);
				free (tmp);
 				if (IS_DIGIT (*value)) {
 					if (strchr (value, '/')) {
 						node->i_value = r_num_get (cfg->num, value);
					} else {
						node->i_value = r_num_math (cfg->num, value);
					}
				} else {
					node->i_value = 0;
				}
				node->flags |= CN_INT;
			}
		}
	} else { // Create a new RConfigNode
		oi = UT64_MAX;
		if (!cfg->lock) {
			node = r_config_node_new (name, value);
			if (node) {
				if (value && is_bool (value)) {
					node->flags |= CN_BOOL;
					node->i_value = is_true (value)? 1: 0;
				}
				if (cfg->ht) {
					ht_insert (cfg->ht, node->name, node);
					r_list_append (cfg->nodes, node);
					cfg->n_nodes++;
				}
			} else {
				eprintf ("r_config_set: unable to create a new RConfigNode\n");
			}
		} else {
			eprintf ("r_config_set: variable '%s' not found\n", name);
		}
	}

	if (node && node->setter) {
		int ret = node->setter (cfg->user, node);
		if (ret == false) {
			if (oi != UT64_MAX) {
				node->i_value = oi;
			}
			free (node->value);
			node->value = strdup (ov? ov: "");
		}
	}
beach:
	free (ov);
	return node;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.