# CVE-2026-100869: Sylius Shop API payment refund authorization bypass

Source: https://junglewise.ai/threats/cve-2026-100869-sylius-versions-before-2-1-16-and-2-2-9-fail-to-restrict-payment  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-27. Updated: 2026-09-27  
License: CC BY 4.0 with a link back

CVE-2026-100869 · Severity: medium · CVSS 5.9 · Published 2026-09-27

Sylius, an open-source e-commerce platform, fails to properly validate payment actions in its Shop API, allowing customers to trigger unauthorized refunds on completed orders. An attacker with a customer's order token can submit arbitrary payment requests like refunds that payment gateways will execute, while Sylius incorrectly maintains the order as paid—resulting in direct financial loss to merchants.

Technologies: [Sylius](https://junglewise.ai/threats/technologies/sylius). Vendors: [Sylius](https://junglewise.ai/threats/vendors/sylius).

## Quick answers

**Is CVE-2026-100869 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100869 being exploited in the wild.

**How severe is CVE-2026-100869?** Medium severity, with a CVSS score of 5.9, published 27 September 2026.

**Which products and versions are affected?** Sylius before 2.1.16 and 2.2.9.

**Is there a fix for CVE-2026-100869?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-100869 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-100869?** Check whether you run Sylius at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The Shop API endpoint does not restrict payment action submissions, allowing customers to request arbitrary payment operations including refunds via order tokens. Attackers can bypass authorization checks by submitting payment actions that payment gateways process while Sylius fails to synchronize the order state, resulting in funds being refunded while the merchant's records show the order as paid. The vulnerability affects Sylius before versions 2.1.16 and 2.2.9.

## Affected products

- Sylius Sylius before 2.1.16 and 2.2.9

## Timeline

- 2026-09-27: disclosed

## References

- [https://packagist.org/](https://packagist.org/)
- [https://github.com/Sylius/Sylius](https://github.com/Sylius/Sylius)

## Related threats

- [Sylius authorization bypass in product review API](https://junglewise.ai/threats/cve-2026-108724-sylius-through-2-3-0-contains-an-authorization-bypass)
- [Sylius payment amount validation bypass in cart recalculation](https://junglewise.ai/threats/cve-2026-100872-sylius-versions-before-2-1-16-and-2-2-9-fail-to-validate-payment)
- [Sylius JWT token firewall identification bypass](https://junglewise.ai/threats/cve-2026-100871-sylius-versions-before-1-12-25-1-13-17-1-14-20-2-1-16-and-2-2-9)
- [Sylius password-reset link Host header injection](https://junglewise.ai/threats/cve-2026-100870-sylius-versions-before-1-12-25-1-13-17-1-14-20-2-1-16-and-2-2-9)
- [Sylius IDOR in Shop Payment Request API endpoints](https://junglewise.ai/threats/cve-2026-53639-sylius-idor-in-shop-payment-request-api-endpoints)