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.
Upstream:released (3.4.20+dfsg-1)
Ubuntu 12.04 ESM (Precise Pangolin):DNE
Ubuntu 14.04 ESM (Trusty Tahr):DNE
Ubuntu 16.04 LTS (Xenial Xerus):needed
Ubuntu 18.04 LTS (Bionic Beaver):needed
Ubuntu 20.04 LTS (Focal Fossa):not-affected (3.4.20+dfsg-1)
Ubuntu 20.10 (Groovy Gorilla):not-affected (3.4.20+dfsg-1)
More Information

Updated: 2020-09-09 22:06:08 UTC (commit b67d7d8b03f173f825cd706df5bd078bca500b0e)