CVE-2026-55888

High

Description

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.

SeverityHigh
CVSS8.8
Exploit probability—
ProductFlatpak Xdg-desktop-portal
PublishedOct 23, 2026
First seenOct 23, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
flatpak xdg-desktop-portal< 1.22.1—

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