Image URL Retrieval via PDF Content Injection Leaks Server Info and Enables SSRF

Content injected to PDF rendering contexts could, in many places, include HTML content including <img> tags. If the src attribute of these images pointed to an URL, the PDF rendering engine would download the image from that place and display it, thereby leaking information about the rendering server and possibly creating an SSRF vector in the local network.

Phishing via Uncontrolled HTML Injection on Redirected Pages

Malicious HTML content could be injected into the page pretix shows when redirection to an untrusted page occurs. Since this page has a Content-Security-Policy, this can mainly be used for phishing purposes.

Incorrect Permission Check During Room Creation in Venueless

Permissions where checked incorrectly during room creation, allowing attackers to create rooms of types they shouldn't be allowed to create.

XLSX formula injection in exports

Untrusted user data was passed verbatim to Excel exports for administrators. This allowed formula injection which can be used to compromise the environment of the user loading the file or other data in the file.

Open redirect

An unvalidated redirect was contained in Venueless' social login functionality and could be exploited for phishing using trusted domains.

Data exposed without proper permission

When creating an export of all reusable media, the secrets of connected gift cards were included in the export even if the user creating the export does not have permission to view gift cards. This is inconsistent with the UI and API where only the first letters of the gift card secret are shown. Therefore, it allows circumventing a permission boundary.

Insecure direct object reference

When creating an export through the pretix API, API clients are returned an UUID value for their export job (a long, random string like 35742818-c375-4d15-839f-d49aecce94d6). Using this UUID, the API client can then request the actual file for download. The same kind of UUID is used in other places in pretix when temporary files are generated for internal use or download. One remaining API endpoint, however, wrongfully did not verify if the UUID used for download actually belongs to a file that is supposed to be downloadable and belongs to the correct user. In reality, this is hard to exploit because an attacker would need to have access to a valid UUID for the file they desire which is unlikely to happen without a separate security problem giving them access to logs etc.

API Endpoint Exposes All Check‑In Events to Unauthorized Users

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.

Unsafe variable evaluation in email templates

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 two security-relevant bugs: * 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 the email subject. * Placeholders in subjects and plain text bodies of emails were wrongfully evaluated twice. Therefore, if the first evaluation of a placeholder again contains a placeholder, this second placeholder was rendered. This allows the rendering of placeholders controlled by the ticket buyer, and therefore the exploitation of the first issue as a ticket buyer. Luckily, the only buyer-controlled placeholder available in pretix by default (that is not validated in a way that prevents the issue) is {invoice_company}, which is very unusual (but not impossible) to be contained in an email subject template. In addition to broadening the attack surface of the first issue, this could theoretically also leak information about an order to one of the attendees within that order. However, we also consider this scenario very unlikely under typical conditions. 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.

Unsafe variable evaluation in email templates

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 file.

Unsafe variable evaluation in email templates

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.

Insecure direct object reference

Multiple API endpoints allowed access to sensitive files from other users by knowing the UUID of the file that were not intended to be accessible by UUID only.

Insecure direct object reference

An API endpoint allowed access to sensitive files from other users by knowing the UUID of the file that were not intended to be accessible by UUID only.

API allows deletion of users of other instance

A user with API access and "manage users" permission in any venueless world is able to trigger deletion of user accounts in other worlds.

Unauthorized access to chat contents

A user with permission "update world" in any Venueless world is able to exfiltrate chat messages from direct messages or channels in other worlds on the same server due to a bug in the reporting feature. The exploitability is limited by the fact that the attacker needs to know the internal channel UUID of the chat channel, which is unlikely to be obtained by an outside attacker, especially for direct messages.

Limited HTML injection in emails

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.

pretix before 2024.1.1 mishandles file validation.

Stored XSS in Placeholder Samples in Mail Preview

Stored XSS in organizer and event settings of pretix up to 2024.7.0 allows malicious event organizers to inject HTML tags into e-mail previews on settings page. The default Content Security Policy of pretix prevents execution of attacker-provided scripts, making exploitation unlikely. However, combined with a CSP bypass (which is not currently known) the vulnerability could be used to impersonate other organizers or staff users.