alf.io is an open source ticket reservation system for conferences, trade shows, workshops, and meetups. Prior to version 2.0-M5, a race condition allows the user to bypass the limit on the number of promo codes and use the discount coupon multiple times. In "alf.io", an event organizer can apply price discounts by using promo codes to your events. The organizer can limit the number of promo codes that will be used for this, but the time-gap between checking the number of codes and restricting the use of the codes allows a threat actor to bypass the promo code limit. Version 2.0-M5 fixes this issue.
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.
| Link | Tags |
|---|---|
| https://github.com/alfio-event/alf.io/security/advisories/GHSA-67jg-m6f3-473g | exploit vendor advisory |
| https://github.com/alfio-event/alf.io/commit/53b3309e26e8acec6860d1e045df3046153a3245 | patch |