pretix before 2024.1.1 mishandles file validation.

Emails sent by pretix can utilize placeholders that will be filled with customer data. For example, when {name} is used in an email template, it will be replaced with the buyer's name for the final email. If the name of the attendee contained HTML or Markdown formatting, this was rendered as HTML in the resulting email. This way, a user could inject links or other formatted text through a maliciously formatted name. Since pretix applies a strict allow list approach to allowed HTML tags, this could not be abused for XSS or similarly dangerous attack chains. However, it can be used to manipulate emails in a way that makes user-provided content appear in a trustworthy and credible way, which can be abused for phishing.

Emails sent by pretix can utilize placeholders that will be filled with customer data. For example, when {name} is used in an email template, it will be replaced with the buyer's name for the final email. This mechanism contained a security-relevant bug: It was possible to exfiltrate information about the pretix system through specially crafted placeholder names such as {{event.__init__.__code__.co_filename}}. This way, an attacker with the ability to control email templates (usually every user of the pretix backend) could retrieve sensitive information from the system configuration, including even database passwords or API keys. pretix does include mechanisms to prevent the usage of such malicious placeholders, however due to a mistake in the code, they were not fully effective for this plugin. Out of caution, we recommend that you rotate all passwords and API keys contained in your pretix.cfg https://docs.pretix.eu/self-hosting/config/  file.

A new API endpoint introduced in pretix 2025 that is supposed to return all check-in events of a specific event in fact returns all check-in events belonging to the respective organizer. This allows an API consumer to access information for all other events under the same organizer, even those they should not have access to. These records contain information on the time and result of every ticket scan as well as the ID of the matched ticket. Example: { "id": 123, "successful": true, "error_reason": null, "error_explanation": null, "position": 321, "datetime": "2020-08-23T09:00:00+02:00", "list": 456, "created": "2020-08-23T09:00:00+02:00", "auto_checked_in": false, "gate": null, "device": 1, "device_id": 1, "type": "entry" } An unauthorized user usually has no way to match these IDs (position) back to individual people.