A local sandbox escape and host information disclosure flaw was found in Yelp. A regression introduced in the companion yelp-xsl stylesheet component targets the gnome-42 and master development branches, leaving the application's Content Security Policy (CSP) style handling directives overly permissive.

A malicious or compromised sandboxed Flatpak application can programmatically abuse the standard host org.freedesktop.portal.OpenURI portal interface to pass crafted help layout files (ghelp:// or mallard extensions). Because the system portal processes this request silently without requiring user interaction, host-level Yelp is automatically invoked to parse the file outside the application container. The attacker-controlled layout leverages local XML inclusions to load arbitrary host-level files into memory, which are subsequently exfiltrated out-of-band to a remote server using a background CSS url() query embedded inside a structured SVG document.

Yelp, the GNOME user help application, allows help documents to execute arbitrary JavaScript. A malicious help document may exfiltrate user files to a remote server.

An issue was discovered in Yelp OSXCollector. A maliciously crafted Universal/fat binary can evade third-party code signing checks. By not completing full inspection of the Universal/fat binary, the user of the third-party tool will believe that the code is signed by Apple, but the malicious unsigned code will execute.