Flatpak XDG Desktop Portal up to 1.22.0 FileChooser.SaveFiles sandbox

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Flatpak XDG Desktop Portal up to 1.22.0. The affected element is the function FileChooser.SaveFiles. The manipulation leads to sandbox. This vulnerability is listed as CVE-2026-55888. The attack must be carried out locally. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Flatpak XDG Desktop Portal up to 1.22.0. This issue affects the function FileChooser.SaveFiles. The manipulation with an unknown input leads to a sandbox vulnerability. Using CWE to declare the problem leads to CWE-265. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-55888 since 06/17/2026. The exploitation is known to be easy. Attacking locally is a requirement. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1611 according to MITRE ATT&CK.

Upgrading to version 1.22.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-108752). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• Flatpak

Name

• XDG Desktop Portal

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22.0

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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