CVE-2026-109391
Square Squash through commit e73f280 Unauthenticated YAML Deserialization via Symbolication API
CVSS Score
8.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-502 |
| Vendor | square |
| Product | squash |
| Published | Oct 12, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
Square / Squash
0 ≤ e73f2805f9eb30780a5c213b001f0f4255660fbf
References
hackmd.io: https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/HJ87QX5ifg github.com: https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/controllers/api/v1_controller.rb github.com: https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/config/preinitializers/safe_yaml.rb github.com: https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/lib/workers/symbolication_creator.rb github.com: https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/models/symbolication.rb github.com: https://github.com/SquareSquash/web vulncheck.com: https://www.vulncheck.com/advisories/square-squash-through-commit-e73f280-unauthenticated-yaml-deserialization-via-symbolication-api
Credits
hieuPenguinnn