{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "e73f2805f9eb30780a5c213b001f0f4255660fbf"
            }
          ],
          "repo": "https://github.com/SquareSquash/web",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-502"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109391.json"
  },
  "details": "Square Squash through commit e73f280 contains an insecure deserialization vulnerability that allows unauthenticated attackers to store crafted YAML via the POST /api/1.0/symbolication endpoint. When occurrences referencing the attacker-controlled symbolication UUID are symbolicated, the stored values are passed to YAML.load with SafeYAML in unsafe mode, enabling arbitrary Ruby object deserialization and potential code execution.",
  "id": "CVE-2026-109391",
  "modified": "2026-10-15T02:30:56.981144942Z",
  "published": "2026-10-12T15:16:39.257Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109391.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109391"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/square-squash-through-commit-e73f280-unauthenticated-yaml-deserialization-via-symbolication-api"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/SquareSquash/web"
    },
    {
      "type": "ARTICLE",
      "url": "https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/controllers/api/v1_controller.rb"
    },
    {
      "type": "ARTICLE",
      "url": "https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/models/symbolication.rb"
    },
    {
      "type": "ARTICLE",
      "url": "https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/config/preinitializers/safe_yaml.rb"
    },
    {
      "type": "ARTICLE",
      "url": "https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/lib/workers/symbolication_creator.rb"
    },
    {
      "type": "EVIDENCE",
      "url": "https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/HJ87QX5ifg"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Square Squash through commit e73f280 Unauthenticated YAML Deserialization via Symbolication API"
}