Bug 2559766 (CVE-2026-55888)

Summary: CVE-2026-55888 xdg-desktop-portal: xdg-desktop-portal: Unauthorized host file access via unvalidated FileChooser filenames
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in xdg-desktop-portal. An attacker operating a sandboxed application can bypass isolation boundaries to gain unauthorized access to host files. This issue occurs because the FileChooser interface fails to properly validate filenames before passing them to backend services. Consequently, a malicious application can create and manipulate arbitrary files on the host system, limited only by the permissions of the current user.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2565122    
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Description OSIDB Bzimport 2026-10-23 13:33:11 UTC
XDG Desktop Portal is a desktop integration portal. Prior to version 1.22.1, malicious sandboxed applications can use the FileChooser.SaveFiles method to gain arbitrary file access to non-existing files on the host (limited to files the user has access to). The FileChooser.SaveFiles method takes optional filenames which get appended to the selected directory by backends. The backends are supposed to check that the file does not exist yet. The filenames are not validated by the frontend and also not by common backends. This issue has been patched in version 1.22.1.