CVE-2026-13602
HighCVSS 7.7Exploitation Probability (EPSS)
Low risk15th percentile — higher than 15% of all known CVEs
Summary
A chain of vulnerabilities was found in pretix: payment plugins (Stripe, Mollie, OPPWA, BitPay, Payone, SecuConnect, Sofort, Saferpay) do not validate session parameters beyond cryptographic signature, the redirect feature uses the same key and salt for signing as the plugins, and the admin impersonation feature allows changing user after injecting arbitrary parameters. An attacker with access to at least one event can become any backend user and access all data.
Risk Assessment
The organization is at risk of complete user account takeover and unauthorized access to sensitive data, including payment and personal information, potentially leading to privacy breaches and financial losses.
Recommendation
Immediately update pretix core and all listed payment plugins to the latest releases issued today, which enforce strict session parameter validation, use different salts for signatures, and require unguessable information for session impersonation.
Original NVD description (English source)
We found a chain of combining multiple weaknesses in the product that could allow an attacker to become any user in the backend and access any data: * The payment integration plugins Stripe (included in the core system), pretix-mollie, pretix-oppwa, pretix-bitpay, pretix-payone, pretix-secuconnect, pretix-sofort, and pretix-saferpay contain a code path that is intended for the transport of session parameters from a tab with isolated cookies (e.g. in the pretix widget) to a new tab. For this purpose, a set of session parameters is cryptographically signed and then passed to the new tab as a URL parameter. The plugins perform no further validation of the session parameters, other than the cryptographic signature being valid. This is fixed with the releases issued today by strictly validating that no session parameters outside of the scope of the respective plugin may be set. * An unrelated feature in the core system is used to generate redirect links that obfuscate any Referer headers for outgoing links to prevent leakage of secrets in URLs. This redirect page also requires cryptographically signed parameters. Unfortunately, it uses the same key and salt for the signature as the previously mentioned feature in the payment integration plugins. A motivated attacker with access to at least one event in the backend can trick the system into cryptographically signing arbitrary content using specially crafted links. In combination with the previous issue, the attacker could use this to set and modify arbitrary parameters on their user session by injecting the signed parameters into the feature of the payment providers. This is fixed with the releases issued today by using different salts for the signature for each plugin and feature. * A third, unrelated feature in the core system is used for admin users to act on behalf of another user, mostly for debugging purposes. With being able to insert arbitrary parameters into a session, an attacker can abuse this feature to change their session from their actual user to any user in the system by guessing a valid user ID. This is fixed with the release today by requiring unguessable information to be contained in the session of the user to switch to.