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.
References7
- github.com/SquareSquash/web
- github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f…
- github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f…
- github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f…
- github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f…
- hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/HJ87QX5ifg
- www.vulncheck.com/advisories/square-squash-through-commit-e73f2…
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 4.0
-
9.2
CRITICAL
Score source: CNA
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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 42 · as of 11 November 2026
- CWE
- CWE-502
Could this be exploited in your environment?
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