CVE-2018-19789

Severity: medium (CVSS 5.3 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-12-18 · updated 2026-06-17
Weakness: CWE-434

Description

An issue was discovered in Symfony 2.7.x before 2.7.50, 2.8.x before 2.8.49, 3.x before 3.4.20, 4.0.x before 4.0.15, 4.1.x before 4.1.9, and 4.2.x before 4.2.1. When using the scalar type hint `string` in a setter method (e.g. `setName(string $name)`) of a class that's the `data_class` of a form, and when a file upload is submitted to the corresponding field instead of a normal text input, then `UploadedFile::__toString()` is called which will then return and disclose the path of the uploaded file. If combined with a local file inclusion issue in certain circumstances this could escalate it to a Remote Code Execution.

Affected products

Debian Linux: 8.0
symfony: from 2.7.0 before 2.7.50; from 2.8.0 before 2.8.49; from 3.0.0 before 3.4.20; from 4.0.0 before 4.0.15; from 4.1.0 before 4.1.9; from 4.2.0 before 4.2.1 — fixed in 2.7.50, 2.8.49, 3.4.20, 4.0.15, 4.1.9, 4.2.1

How to fix

Upgrade to a fixed version: symfony 2.7.50, 2.8.49, 3.4.20, 4.0.15. Check the vendor advisory for mitigations.

References

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