{"id":"CVE-2026-109391","summary":"Square Squash through commit e73f280 Unauthenticated YAML Deserialization via Symbolication API","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.","modified":"2026-10-14T02:47:46.658954490Z","published":"2026-10-12T15:16:39.257Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109391.json","cna_assigner":"VulnCheck","cwe_ids":["CWE-502"]},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/SquareSquash/web","events":[{"introduced":"0"},{"last_affected":"e73f2805f9eb30780a5c213b001f0f4255660fbf"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-109391.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","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"}]}