title: Possible Information Leak Vulnerability in Action View
description: "\nThere is a possible directory traversal and information leak vulnerability
\nin Action View. This was meant to be fixed on CVE-2016-0752. However the 3.2 \npatch
was not covering all the scenarios. This vulnerability has been \nassigned the CVE
identifier CVE-2016-2097.\n\nVersions Affected: 3.2.x, 4.0.x, 4.1.x\nNot affected:
\ 4.2+\nFixed Versions: 18.104.22.168, 22.214.171.124\n\nImpact \n------ \nApplications
that pass unverified user input to the `render` method in a\ncontroller may be vulnerable
to an information leak vulnerability.\n\nImpacted code will look something like
this:\n\n```ruby\ndef index\n render params[:id]\nend\n```\n\nCarefully crafted
requests can cause the above code to render files from\nunexpected places like outside
the application's view directory, and can\npossibly escalate this to a remote code
execution attack.\n\nAll users running an affected release should either upgrade
or use one of the\nworkarounds immediately.\n\nReleases \n-------- \nThe FIXED releases
are available at the normal locations. \n\nWorkarounds \n----------- \nA workaround
to this issue is to not pass arbitrary user input to the `render`\nmethod. Instead,
verify that data before passing it to the `render` method.\n\nFor example, change
this:\n\n```ruby\ndef index\n render params[:id]\nend\n```\n\nTo this:\n\n```ruby\ndef
index\n render verify_template(params[:id])\nend\n\nprivate\ndef verify_template(name)\n
\ # add verification logic particular to your application here\nend\n```\n\nPatches
\n------- \nTo aid users who aren't able to upgrade immediately we have provided
patches \nfor it. It is in git-am format and consist of a single changeset.\n\n*
3-2-render_data_leak_2.patch - Patch for 3.2 series\n* 4-1-render_data_leak_2.patch
- Patch for 4.1 series\n\nCredits \n------- \nThanks to both Jyoti Singh and Tobias
Kraze from makandra for reporting this \nand working with us in the patch!\n"
- ">= 4.1.0"
- "~> 126.96.36.199"
- "~> 4.1.14, >= 188.8.131.52"