CVE-2026-5600: pretix API Leaks Check-in Data Between Vulnerability

MODERATE
Advisory Identifier: GHSA-wr8q-c73g-m7gp
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CWE-653
Published
Advisory Summary

CVE-2026-5600 is a MODERATE api leaks check-in data between vulnerability (CWE-653: Improper Isolation or Compartmentalization) affecting pretix libraries in the PyPI ecosystem. The issue involves api leaks check-in data between events of the same organizer. Remediation is available by upgrading affected packages to version 2026.3.1, 2026.2.1, 2026.1.2.

CVE-2026-5600 at a Glance

CVE Identifier CVE-2026-5600
GHSA Identifier GHSA-wr8q-c73g-m7gp
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-653: Improper Isolation or Compartmentalization
Affected Product pretix
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-5600

To remediate this vulnerability, upgrade all affected pretix dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

pretix fixed: 2026.3.1 
pip install pretix>=2026.3.1
pretix fixed: 2026.2.1 
pip install pretix>=2026.2.1
pretix fixed: 2026.1.2 
pip install pretix>=2026.1.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show pretix

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-5600, inspect your installed packages using pip:

pip show pretix

Analyze the terminal output to locate any version of pretix in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2026.3.1), your application is affected.

Note: The pip show pretix command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-653: Improper Isolation or Compartmentalization, where the product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions. In pretix, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-5600 Affected pretix Versions

3 component(s)
Fixed Versions:
2026.3.12026.2.12026.1.2
Product / Package Ecosystem Affected Versions Fixed Version
pretix
pypi/pretix
PyPI
≥ 2026.3.0
< 2026.3.1
2026.3.1
pretix
pypi/pretix
PyPI
≥ 2026.2.0
< 2026.2.1
2026.2.1
pretix
pypi/pretix
PyPI
≥ 2025.10.0
< 2026.1.2
2026.1.2

References

NVD — CVE-2026-5600 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-5600
pretix Source Repository REPOSITORY
https://github.com/pretix/pretix
pretix Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/pretix/PYSEC-2026-111.yaml
pretix Release RELEASE
https://pretix.eu/about/en/blog/20260408-release-2026-3-1

Frequently Asked Questions

What is CVE-2026-5600?
CVE-2026-5600 is a security vulnerability in pretix involving API leaks check-in data between events of the same organizer under CWE-653: Improper Isolation or Compartmentalization.
Which pretix versions are affected?
Affected versions include releases prior to 2026.3.1, 2026.2.1, 2026.1.2 across affected packages: pretix.
What version fixes CVE-2026-5600?
Upgrading to 2026.3.1, 2026.2.1, 2026.1.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is pretix affected?
Yes, pretix is affected in releases prior to 2026.3.1, 2026.2.1, 2026.1.2. Upgrade your dependency to 2026.3.1, 2026.2.1, 2026.1.2 or later.
What CWE is associated with CVE-2026-5600?
CVE-2026-5600 is classified under CWE-653: Improper Isolation or Compartmentalization (The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.).
How can I check PyPI dependencies for CVE-2026-5600?
Run the dependency tree command: 'pip show pretix'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-wr8q-c73g-m7gp",
  "modified" : "2026-06-08T19:03:02Z",
  "published" : "2026-04-08T15:31:44Z",
  "aliases" : [ "CVE-2026-5600" ],
  "summary" : "pretix: API leaks check-in data between events of the same organizer",
  "details" : "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.\n\nThese records contain information on the time and result of every ticket scan as well as the ID of the matched ticket. Example:\n\n{\n  \"id\": 123,\n  \"successful\": true,\n  \"error_reason\": null,\n  \"error_explanation\": null,\n  \"position\": 321,\n  \"datetime\": \"2020-08-23T09:00:00+02:00\",\n  \"list\": 456,\n  \"created\": \"2020-08-23T09:00:00+02:00\",\n  \"auto_checked_in\": false,\n  \"gate\": null,\n  \"device\": 1,\n  \"device_id\": 1,\n  \"type\": \"entry\"\n}\n\nAn unauthorized user usually has no way to match these IDs (position) back to individual people.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pretix"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2026.3.0"
      }, {
        "fixed" : "2026.3.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pretix"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2026.2.0"
      }, {
        "fixed" : "2026.2.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pretix"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2025.10.0"
      }, {
        "fixed" : "2026.1.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-5600"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pretix/pretix"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/pretix/PYSEC-2026-111.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://pretix.eu/about/en/blog/20260408-release-2026-3-1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-653" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-08T19:23:39Z",
    "nvd_published_at" : "2026-04-08T13:16:43Z"
  }
}