Rails Action View - Path Traversal (CVE-2019-5418)

CVE-2019-5418 is a file content disclosure vulnerability in multiple versions of Rails' Action View, where attackers can exploit specially crafted HTTP accept headers to access arbitrary files on the server. This flaw could be leveraged by remote, unauthenticated attackers to read sensitive files, potentially exposing confidential information and aiding in further attacks.

CrowdSec has been tracking this vulnerability and its exploits since 5th of August 2025.

CrowdSec network observations suggest that most exploitation of CVE-2019-5418 involves focused reconnaissance to identify viable targets. Attackers typically tailor their campaigns based on system exposure and configuration. It is unlikely that a given attack is accidental. Telemetry from the CrowdSec network also shows that exploitation activity for CVE-2019-5418 remains steady week-over-week. Attack volumes are consistent with long-term trends, indicating sustained interest from threat actors. CVE-2019-5418 continues to be an active part of the threat landscape and will likely remain this way for the forseeable future.

Attackers exploit this vulnerability by sending GET requests with a malicious Accept header containing path traversal sequences to disclose sensitive files, but detection is not possible without header inspection.