Flatpak Sandbox Escape via Yelp (CVE-2025-3155) Analysis

Vulnerability Overview Vulnerability Name: Flatpak Sandbox Escape via Yelp CVE ID: CVE-2025-3155 Publication Date: May 11, 2026 Description: Yelp 49.1 addressed a Flatpak sandbox escape vulnerability related to CVE-2025-3155 from last year. This vulnerability allows sandboxed applications to launch other applications by opening URIs or file paths. The process is conducted through the OpenURI portal, which may or may not require user interaction to decide which application to launch, although user interaction is typically not required. Scope of Impact Affected Applications: Flatpak sandboxed applications Potential Risks: A malicious sandboxed application can launch unsandboxed applications using malicious files, often without requiring user interaction. Unsandboxed applications are installed on the host system and constitute part of the attack surface for Flatpak sandbox attacks. Specific Case: A sandboxed application can launch Yelp to open a malicious help file. The help file can extract arbitrary files from the host operating system to a web server via CSS stylesheets embedded in SVG. Remediation Fixed Version: Yelp 49.1 Fix Details: Addressed the Flatpak sandbox escape vulnerability related to CVE-2025-3155. Update Information: On June 29, 2026, CVE-2026-13601 was assigned. POC Code or Exploit Code No Specific Code: No specific POC code or exploit code was provided in this page. Additional Information Discoverer: Codean Labs Sponsor: Sovereign Tech Resilience program by the German Sovereign Tech Institution Related Projects: Flatpak and multiple GNOME projects --- Summary: This vulnerability involves Flatpak sandboxed applications exploiting Yelp to open malicious files, leading to sandbox escape. The remediation is to upgrade to Yelp version 49.1.

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Flatpak Sandbox Escape via Yelp (CVE-2025-3155) Analysis