J2Commerce J2Store Extension up to 6.0.0/6.6.5 Checkout max_uses/max_customer_uses toctou

Summaryinfo

A vulnerability was found in J2Commerce J2Store Extension up to 6.0.0/6.6.5. It has been declared as problematic. This impacts an unknown function of the component Checkout. Such manipulation of the argument max_uses/max_customer_uses leads to toctou. This vulnerability is listed as CVE-2026-102803. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in J2Commerce J2Store Extension up to 6.0.0/6.6.5. Affected by this issue is some unknown processing of the component Checkout. The manipulation of the argument max_uses/max_customer_uses with an unknown input leads to a toctou vulnerability. Using CWE to declare the problem leads to CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. Impacted is integrity. CVE summarizes:

Joomla Extension - j2commerce.com - Gift voucher and single-use coupon could pay for more than one order in J2Store 6.0.0 - 6.6.5 - A logged-in customer could redeem a single gift voucher, or a single-use coupon (`max_uses` / `max_customer_uses` = 1), on more than one order. By starting several checkout sessions and carrying each to the confirm step before submitting any of them, every order independently saw the voucher's full balance or the coupon's unused slot, because the balance/usage calculations and the final placement check both only looked at orders that had already left the "New" state.

The advisory is available at j2commerce.com. This vulnerability is handled as CVE-2026-102803 since 09/29/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• J2Commerce

Name

• J2Store Extension

Version

• 6.0
• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

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• 🔒

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