CVE-2026-109391

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.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/SquareSquash/web
https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/controllers/api/v1_controller.rb
https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/models/symbolication.rb
https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/config/preinitializers/safe_yaml.rb
https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/lib/workers/symbolication_creator.rb
https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/HJ87QX5ifg
https://www.vulncheck.com/advisories/square-squash-through-commit-e73f280-unauthenticated-yaml-deserialization-via-symbolication-api

Configurations

No configuration.

History

12 Oct 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-12 16:17

Updated : 2026-10-16 18:25

NVD link : CVE-2026-109391

Mitre link : CVE-2026-109391

CVE.ORG link : CVE-2026-109391

JSON object : View

Products Affected

No product.

CWE

CWE-502

Deserialization of Untrusted Data

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