CVE-2026-102803j2commerce.com J2Store extension for Joomla time-of-check to time-of-use race
CVE-2026-102803 is a time-of-check to time-of-use race in j2commerce.com J2Store extension for Joomla, rated medium (6.0 on CVSS 4.0).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Received
What it is
Something is checked, then changed by an attacker before it is used.
How it is reached
An attacker can exploit it over the network, with an ordinary user account, and nobody has to click anything. Success also depends on conditions the attacker does not fully control.
What an attacker gains
A successful attack can change data or behaviour. In practice, this kind of flaw lets an attacker win a timing window to bypass a check or corrupt shared state.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- No fixed version is listed yet. Find every place j2commerce.com J2Store extension for Joomla runs, watch the references for a fix, and plan a replacement if it is no longer supported.
- While there is no fix, review who holds accounts that can reach it.
Description from NVD
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.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Request handlers and jobs that share state. The flaw sits between concurrent requests or processes.
Trust boundaries in play
- Authenticated network access. An account is needed, so exposure follows who can sign in: customers, partners or staff.
- Between concurrent requests or processes. An attacker who crosses it can win a timing window to bypass a check or corrupt shared state.
Questions to answer about your own systems
- Where does j2commerce.com J2Store extension for Joomla run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.