{"id":"CVE-2026-109391","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-109391","generatedAt":"2026-10-28T01:11:58.456Z","title":"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.","description":"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.","published":"2026-10-12T16:17:04.000Z","lastModified":"2026-10-16T18:25:45.000Z","status":"Deferred","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":9.2,"severity":"CRITICAL","vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-502"],"affected":[],"epss":{"score":0.00477,"percentile":0.40927,"date":"2026-10-26","history":[{"date":"2026-10-13","score":0.00477,"percentile":0.39462}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.48%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-12T16:17:04.000Z","detail":{"score":"9.2","severity":"CRITICAL","publishedAt":"2026-10-12T16:17:04.373Z"},"summary":"New CVE, critical severity (CVSS 9.2)."}],"references":[{"url":"https://github.com/SquareSquash/web","source":"disclosure@vulncheck.com"},{"url":"https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/controllers/api/v1_controller.rb","source":"disclosure@vulncheck.com"},{"url":"https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/models/symbolication.rb","source":"disclosure@vulncheck.com"},{"url":"https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/config/preinitializers/safe_yaml.rb","source":"disclosure@vulncheck.com"},{"url":"https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/lib/workers/symbolication_creator.rb","source":"disclosure@vulncheck.com"},{"url":"https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/HJ87QX5ifg","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/square-squash-through-commit-e73f280-unauthenticated-yaml-deserialization-via-symbolication-api","source":"disclosure@vulncheck.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-109391","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}