MISP Path Traversal in OrgImgHelper findOrgImage via Crafted Organization Name

The findOrgImage method in MISP's OrgImgHelper constructs a filesystem path by concatenating a user-supplied organization identifier with a fixed image directory and a file extension, then calls file_exists() on the resulting path. The organization name field is attacker-controllable through event import, which sets Org.name. Because no validation was performed on the field value before path construction, an organization name containing directory traversal sequences (e.g., ../../etc/passwd) would cause the path to resolve outside the intended org-image directory.  This yields two security impacts:   - an arbitrary file existence oracle, since file_exists() returns a boolean for any path the process can access.  - an arbitrary file read limited to files with .png or .svg extensions, because the resolved filename is returned and subsequently rendered or served to the requesting user. The vulnerability requires an authenticated user with the ability to create or import events that set the organization name.