---
title: "BigCommerce Checkout ignores malformed cart IDs: 2026-10-19 | Harbyn"
description: "BigCommerce Checkout ignores malformed cart IDs, announced Oct 19, 2026."
canonical: "https://harbyn.com/changes/bigcommerce/2026-10-19-checkout-no-longer-returns-an-error-for-a-malformed-cart-id"
last-updated: 2026-10-25
---

# BigCommerce Checkout ignores malformed cart IDs

Markdown version of <https://harbyn.com/changes/bigcommerce/2026-10-19-checkout-no-longer-returns-an-error-for-a-malformed-cart-id>.

Behavior change - BigCommerce. low severity. In effect.

Checkout requests with cart\_id as an array no longer return HTTP 500; the page ignores the non-string value and continues with the shopper's primary cart.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [BigCommerce](https://harbyn.com/vendors/bigcommerce.md) |
| Kind | Behavior change |
| Severity | low |
| Status | In effect |
| Announced | Oct 19, 2026 |
| Added to Harbyn | Oct 25, 2026 |
| Lead time | No dated deadline |
| Symbols | `cart_id` |
| Review | Reviewed by a person, extracted by a model |

## Find it in your code

```sh
npx harbyn scan
```

This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses BigCommerce, from its packages and API hosts. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://docs.bigcommerce.com/developer/changelog.md> (changelog, fetched 2026-10-21 14:31 UTC, sha256 `d9aef4e166bd4bff8d4bb395a8a1c1d0e0b16f751858417396c88d05fcc6fa9c`)

## Related changes

### More from BigCommerce

- [Atomic storefront session rotation](https://harbyn.com/changes/bigcommerce/2026-10-16-atomic-storefront-session-rotation.md) (Behavior change, announced Oct 16, 2026)
- [Braintree Pay by bank requests use production credentials and environment](https://harbyn.com/changes/bigcommerce/2026-10-14-braintree-pay-by-bank-now-reaches-the-right-braintree-account.md) (Behavior change, announced Oct 14, 2026)
- [PayPal Commerce Platform order details sent to PayPal](https://harbyn.com/changes/bigcommerce/2026-10-13-paypal-commerce-platform-order-details-sent-to-paypal.md) (Behavior change, announced Oct 13, 2026)
- [Affirm orders with many products no longer remain Incomplete](https://harbyn.com/changes/bigcommerce/2026-10-09-affirm-orders-with-many-products-are-no-longer-stuck-in-incomplete-status.md) (Behavior change, announced Oct 9, 2026)

### Changes at other vendors

- [Amazon Selling Partner API: ORDER\_CHANGE notifications add PreFulfillmentStatusChange for Amazon Autos](https://harbyn.com/changes/amazon-sp-api/2026-10-14-sp-api-updates-new-listings-items-api-ivp-values-in-eu5-jp-and-ca-stores-oct-3.md) (effective Oct 28, 2026)
- [GitHub: Secret scanning audit log business field changes to enterprise slug](https://harbyn.com/changes/github/2026-10-20-updates-to-github-secret-scanning-7.md) (effective Nov 12, 2026)
- [Jira / Atlassian Cloud: New IP address ranges in use from January 1, 2027](https://harbyn.com/changes/atlassian-jira/2026-10-16-atlassian-cloud-adds-new-ip-address-ranges.md) (effective Jan 1, 2027)
- [Let's Encrypt: Default certificate lifetime changes to 64 days](https://harbyn.com/changes/letsencrypt/2026-10-07-64-day-certificate-lifetimes-coming-feb-2027.md) (effective Feb 10, 2027)

[All upcoming deadlines](https://harbyn.com/deadlines.md)