Vulnerability Description
In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj
- https://www.openwall.com/lists/oss-security/2026/08/11/9
FAQ
What is CVE-2026-90616?
CVE-2026-90616 is a vulnerability with a CVSS score of 7.4 (HIGH). In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnera...
How severe is CVE-2026-90616?
CVE-2026-90616 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-90616?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.