channel_register_filter(int id, channel_infilter_fn *ifn,
    channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
{
	Channel *c = channel_lookup(id);

	if (c == NULL) {
		logit("channel_register_filter: %d: bad id", id);
		return;
	}
	c->input_filter = ifn;
	c->output_filter = ofn;
	c->filter_ctx = ctx;
	c->filter_cleanup = cfn;
}

This category addresses vulnerabilities caused by flawed access control mechanisms, where incorrect permission settings allow unauthorized users to access restricted resources.