GHSA-vx9j-46rh-fqr8

There is a possible directory traversal and information leak vulnerability in Action View. This was meant to be fixed on CVE-2016-0752. However the 3.2 patch was not covering all possible scenarios. This vulnerability has been assigned the CVE identifier CVE-2016-2097.

Versions Affected: 3.2.x, 4.0.x, 4.1.x Not affected: 4.2+ Fixed Versions: 3.2.22.2, 4.1.14.2

Impact ------ Applications that pass unverified user input to the `render` method in a controller may be vulnerable to an information leak vulnerability.

Impacted code will look something like this:

```ruby def index render params[:id] end ```

Carefully crafted requests can cause the above code to render files from unexpected places like outside the application's view directory, and can possibly escalate this to a remote code execution attack.

All users running an affected release should either upgrade or use one of the workarounds immediately.

Releases -------- The FIXED releases are available at the normal locations.

Workarounds ----------- A workaround to this issue is to not pass arbitrary user input to the `render` method. Instead, verify that data before passing it to the `render` method.

For example, change this:

```ruby def index render params[:id] end ```

To this:

```ruby def index render verify_template(params[:id]) end

private def verify_template(name) # add verification logic particular to your application here end ```

Patches ------- To aid users who aren't able to upgrade immediately we have provided patches for it. It is in git-am format and consist of a single changeset.

* 3-2-render_data_leak_2.patch - Patch for 3.2 series * 4-1-render_data_leak_2.patch - Patch for 4.1 series

Credits ------- Thanks to both Jyoti Singh and Tobias Kraze from makandra for reporting this and working with us in the patch!