CVE-2026-55889: CWE-330: Use of Insufficiently Random Values in flatpak xdg-desktop-portal
Description
XDG Desktop Portal versions prior to 1.22.1 contain a vulnerability where tokens used to grant access to resources are generated using insufficiently random values. This weakness allows a malicious sandboxed application to predict future tokens by analyzing enough generated tokens, enabling it to redirect drag-and-drop and copy-paste data intended for other applications to itself. The issue has been fixed in version 1.22.1.
CVSS v4.0
Score 8.3high
Affected software
flatpak
xdg-desktop-portal
pkg:github/flatpak/xdg-desktop-portalRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
XDG Desktop Portal's token generation mechanism used GLib's GRand based on the Mersenne Twister PRNG, which produces a stream of reproducible random numbers. Tokens generated with g_random_int or g_uuid_string_random could be predicted after observing enough tokens, allowing malicious sandboxed applications to hijack data transfers via the FileTransfer.RetrieveFiles method. This vulnerability is identified as CWE-330 (Use of Insufficiently Random Values) and CWE-337 (Predictable Seed in PRNG). The flaw was patched in version 1.22.1.
Potential Impact
Malicious sandboxed applications can predict tokens that grant access to resources, enabling them to redirect drag-and-drop and copy-paste data intended for other applications to themselves. This compromises data confidentiality and integrity within the desktop environment.
Mitigation Recommendations
Upgrade xdg-desktop-portal to version 1.22.1 or later, where the token generation uses a cryptographically secure random number generator, mitigating the predictability issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-17T16:59:42.760Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6adb5ab74d27ba8daa28669b
Added to database: 10/23/2026, 13:01:43 UTC
Last enriched: 10/23/2026, 13:15:24 UTC
Last updated: 10/23/2026, 13:31:46 UTC
Views: 5
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