Common LaTeX Service Interface (CLSI) before 0.1.3, as used in ShareLaTeX before 0.1.3, allows remote authenticated users to execute arbitrary code via ` (backtick) characters in a filename.
Improper Neutralization of Special Elements used in a Command The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.