A race condition vulnerability in SimplCommerce at commit 230310c8d7a0408569b292c5a805c459d47a1d8f allows attackers to bypass inventory restrictions by simultaneously submitting purchase requests from multiple accounts for the same product. This can lead to overselling when stock is limited, as the system fails to accurately track inventory under high concurrency, resulting in potential loss and unfulfilled orders.
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
A race condition occurs within concurrent environments, and it is effectively a property of a code sequence. Depending on the context, a code sequence may be in the form of a function call, a small number of instructions, a series of program invocations, etc. A race condition violates these properties, which are closely related:
A race condition exists when an “interfering code sequence” can still access the shared resource, violating exclusivity. The interfering code sequence could be “trusted” or “untrusted.” A trusted interfering code sequence occurs within the product; it cannot be modified by the attacker, and it can only be invoked indirectly. An untrusted interfering code sequence can be authored directly by the attacker, and typically it is external to the vulnerable product.