CVE-2026-13603
CriticalCVSS 9.0Exploitation Probability (EPSS)
Low risk17th percentile — higher than 17% of all known CVEs
Summary
The pretix-oppwa plugin insecurely concatenated the resourcePath parameter with the API URL, allowing an attacker to redirect requests to their own server and steal the Oppwa access token. The vulnerability is fixed by strictly validating API URLs.
Risk Assessment
The risk is leakage of the Oppwa account access token, which could allow an attacker to read transaction data and potentially manipulate payments in the organization's system.
Recommendation
Immediately update the pretix-oppwa plugin to the latest version, then request a new access token from your payment provider and update it in the pretix configuration.
Original NVD description (English source)
The payment integration pretix-oppwa provides support for the payment providers VR Payment, Hobex, and potentially others based on Oppwa's technology. The integration of Oppwa, following their official documentation, includes a step where the user is redirected from the payment provider back to our system with a query parameter like ?resourcePath=/v1/checkouts/{checkoutId}/payment in the URL. Our system is then supposed to fetch the status of the transaction from the URL given by baseUrl + resourcePath. Our plugin pretix-oppwa did so insecurely by concatenating the parameter form the URL to the base domain of the API without further validation and, critically, without a / at the end of the baseUrl. Therefore, an attacker could inject a resourcePath argument in a way that causes pretix to call a different server instead. Since the request includes the access token (API key) of the Oppwa account, this would leak the access token, giving access to data contained in the payment provider's system. This is fixed with the release today by strictly validating the given API URL. After installing the update, we recommend asking your payment provider for a new access token and updating it in pretix.