{"id":"DEBIAN-CVE-2026-90616","details":"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.","modified":"2026-09-23T09:00:12.458665524Z","published":"2026-09-12T20:16:30.957Z","upstream":["CVE-2026-90616"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-90616"}],"affected":[{"package":{"name":"flatpak","ecosystem":"Debian:12","purl":"pkg:deb/debian/flatpak?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.14.10-1","1.14.10-1~deb12u1","1.14.10-1~deb12u2","1.14.4-1","1.14.4-1+deb12u1","1.14.4-1+deb12u1~bpo11+1","1.14.4-2","1.14.5-1","1.14.6-1","1.14.6-1~deb13u1","1.14.8-1","1.14.8-1~deb12u1","1.15.0-1","1.15.0-2","1.15.1-1","1.15.10-1","1.15.12-1","1.15.2-1","1.15.3-1","1.15.4-1","1.15.6-1","1.15.7-1","1.15.8-1","1.15.9-1","1.15.91-1","1.16.0-1","1.16.0-2","1.16.0-2~bpo12+1","1.16.1-1","1.16.1-1~bpo12+1","1.16.1-2","1.16.1-3","1.16.2-1","1.16.2-1~deb13u1","1.16.3-1","1.16.3-1~deb13u1","1.16.4-1","1.16.4-2","1.16.5-1","1.16.6-1","1.16.6-1~deb13u1","1.16.6-1~deb13u1~bpo12+1","1.16.6-1~deb13u2","1.17.2-1","1.17.3-1","1.17.3-2","1.17.6-1","1.18.0-1","1.18.1-1","1.18.2-1","1.18.3-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-90616.json"}},{"package":{"name":"flatpak","ecosystem":"Debian:13","purl":"pkg:deb/debian/flatpak?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.16.6-1~deb13u2"}]}],"versions":["1.16.1-1","1.16.1-2","1.16.1-3","1.16.2-1","1.16.2-1~deb13u1","1.16.3-1","1.16.3-1~deb13u1","1.16.4-1","1.16.4-2","1.16.5-1","1.16.6-1~deb13u1","1.16.6-1~deb13u1~bpo12+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-90616.json"}},{"package":{"name":"flatpak","ecosystem":"Debian:14","purl":"pkg:deb/debian/flatpak?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.18.1-1"}]}],"versions":["1.16.1-1","1.16.1-2","1.16.1-3","1.16.2-1","1.16.2-1~deb13u1","1.16.3-1","1.16.3-1~deb13u1","1.16.4-1","1.16.4-2","1.16.5-1","1.16.6-1","1.16.6-1~deb13u1","1.16.6-1~deb13u1~bpo12+1","1.16.6-1~deb13u2","1.17.2-1","1.17.3-1","1.17.3-2","1.17.6-1","1.18.0-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-90616.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}