CVE-2026-90616 - Flatpak Sandbox Escape via Symlink Race Condition
Brief
CVE ID : CVE-2026-90616
Published : Sept. 12, 2026, 8:16 p. m.
- 36 minutes ago
Description : In Flatpak before 1.
- 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.