Terminology before 1.3.1 allows Remote Code Execution because popmedia is mishandled, as…

Summary

Terminology before 1.3.1 allows Remote Code Execution because popmedia is mishandled, as demonstrated by an unsafe "cat README.md" command when \e}pn is used. A popmedia control sequence can allow the malicious execution of executable file formats registered in the X desktop share MIME types (/usr/share/applications). The control sequence defers unknown file types to the handle_unknown_media() function, which executes xdg-open against the filename specified in the sequence. The use of xdg-open for all unknown file types allows executable file formats with a registered shared MIME type to be executed. An attacker can achieve remote code execution by introducing an executable file and a plain text file containing the control sequence through a fake software project (e.g., in Git or a tarball). When the control sequence is rendered (such as with cat), the executable file will be run.