CVE-2026-101274

Improper Validation of response_type Enables Unauthorized Token Issuance in pretix SSO

Published Oct 28, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
Description
When pretix is used as the identity provider in a Single-Sign-On (SSO) setup for customer accounts, the system did not properly validate the `response_type` requested in an authorization request against the configured grant type of the SSO client. This means that if an SSO client was configured to only allow the `code` response type, which requires knowledge of the client secret to use and would wrongfully send a response type like `id_token`, it would receive back a valid token. Exploiting this requires the attacker to run JavaScript on the page specified by `redirect_uri`, which must be from a list specified in the client configuration.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title Improper Validation of response_type Enables Unauthorized Token Issuance in pretix SSO
Type Values Removed Values Added
Title Identity Provider Response Type Validation Bypass in SSO Leading to Token Acquisition
Weaknesses CWE-20
CWE-285
Type Values Removed Values Added
Weaknesses CWE-306
Type Values Removed Values Added
First Time appeared Pretix
Pretix pretix
Vendors & Products Pretix
Pretix pretix
Type Values Removed Values Added
Title Identity Provider Response Type Validation Bypass in SSO Leading to Token Acquisition
Weaknesses CWE-20
CWE-285
Type Values Removed Values Added
Description When pretix is used as the identity provider in a Single-Sign-On (SSO) setup for customer accounts, the system did not properly validate the `response_type` requested in an authorization request against the configured grant type of the SSO client. This means that if an SSO client was configured to only allow the `code` response type, which requires knowledge of the client secret to use and would wrongfully send a response type like `id_token`, it would receive back a valid token. Exploiting this requires the attacker to run JavaScript on the page specified by `redirect_uri`, which must be from a list specified in the client configuration.
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:L/VA:N/SC:H/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
pretix
Published
Updated
Nov 5, 2026, 5:11 PM
Reserved
Sep 28, 2026, 11:48 AM
Status
Deferred
Published
Oct 28, 2026, 11:17 AM
Modified
Nov 5, 2026, 5:17 PM