CVE-2026-109391
Square Squash through commit e73f280 Unauthenticated YAML Deserialization via Symbolication API
- State
- Published
- Severity
- 9.2 Critical
- Published
- Oct 12, 2026
- Updated
- Oct 27, 2026
- Reserved
- Oct 12, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.2 Critical | 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 | VulnCheck |
| 3.1 | 8.1 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-502 Deserialization of Untrusted Data
Affected Products
| Product | Versions |
|---|---|
SquashSquare |
|
References
- Researcher Disclosuretechnical-descriptionexploit
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/controllers/api/v1_controller.rbtechnical-description
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/config/preinitializers/safe_yaml.rbtechnical-description
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/lib/workers/symbolication_creator.rbtechnical-description
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/models/symbolication.rbtechnical-description
- https://github.com/SquareSquash/webproduct
- VulnCheck Advisory: Square Squash through commit e73f280 Unauthenticated YAML Deserialization via Symbolication APIthird-party-advisory
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