Security advisory

{
  "id": "0c18ad2513fac1dc7c005225daccf3a2897afb75b2ee459e237af8d12fc473d4",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-101274",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-101274",
    "summary": "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.",
    "evidence": "cve:CVE-2026-101274",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-101274",
      "aliases": [
        "CVE-2026-101274"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "Safety": "NOT_DEFINED",
            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 6.9,
            "Automatable": "NOT_DEFINED",
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "exploitMaturity": "NOT_DEFINED",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "PASSIVE",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "privilegesRequired": "HIGH",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "affected": [
        {
          "repo": "https://github.com/pretix/pretix",
          "vendor": "pretix",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "2026.6.4",
              "versionType": "python"
            },
            {
              "status": "affected",
              "version": "2026.7.0",
              "lessThan": "2026.7.3",
              "versionType": "python"
            },
            {
              "status": "affected",
              "version": "2026.8.0",
              "lessThan": "2026.8.1",
              "versionType": "python"
            }
          ],
          "packageName": "pretix",
          "collectionURL": "https://pypi.python.org",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-28T10:31:23.485Z",
      "provider": "cve",
      "references": [
        "https://pretix.eu/about/en/blog/20261028-release-2026-8-1/"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "655498c3-6ec5-4f0b-aea6-853b334d05a6",
          "shortName": "pretix",
          "dateUpdated": "2026-10-28T10:31:23.485Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-101274",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 424525,
  "published_at": "2026-10-28T10:31:23.485+00:00"
}