{"id":"UBUNTU-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":"2026-09-16T11:44:18Z","published":"2026-09-12T20:16:00Z","upstream":["CVE-2026-90616"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-90616"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-90616"},{"type":"REPORT","url":"https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj"},{"type":"REPORT","url":"https://www.openwall.com/lists/oss-security/2026/08/11/9"}],"affected":[{"package":{"name":"flatpak","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.8.7-5","0.10.0-1","0.10.0-2","0.10.1-1","0.10.2-1","0.10.2.1-1","0.10.2.1-2","0.10.3-1","0.11.1-0ubuntu1","0.11.3-2","0.11.3-3","0.11.7-0ubuntu0.1","1.0.1-0ubuntu0.1","1.0.6-0ubuntu0.1","1.0.7-0ubuntu0.18.04.1","1.0.8-0ubuntu0.18.04.1","1.0.9-0ubuntu0.1","1.0.9-0ubuntu0.2","1.0.9-0ubuntu0.3","1.0.9-0ubuntu0.4","1.0.9-0ubuntu0.4+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.0.9-0ubuntu0.4+esm1","binary_name":"flatpak"},{"binary_name":"flatpak-tests","binary_version":"1.0.9-0ubuntu0.4+esm1"},{"binary_version":"1.0.9-0ubuntu0.4+esm1","binary_name":"gir1.2-flatpak-1.0"},{"binary_version":"1.0.9-0ubuntu0.4+esm1","binary_name":"libflatpak0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-90616.json"}},{"package":{"name":"flatpak","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.3-1","1.6.0-1","1.6.1-1","1.6.2-1","1.6.3-1","1.6.5-0ubuntu0.1","1.6.5-0ubuntu0.2","1.6.5-0ubuntu0.3","1.6.5-0ubuntu0.4","1.6.5-0ubuntu0.5","1.6.5-0ubuntu0.5+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.6.5-0ubuntu0.5+esm1","binary_name":"flatpak"},{"binary_name":"flatpak-tests","binary_version":"1.6.5-0ubuntu0.5+esm1"},{"binary_name":"gir1.2-flatpak-1.0","binary_version":"1.6.5-0ubuntu0.5+esm1"},{"binary_name":"libflatpak0","binary_version":"1.6.5-0ubuntu0.5+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-90616.json"}},{"package":{"name":"flatpak","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.2-3","1.12.2-1","1.12.2-2","1.12.3-1","1.12.4-1","1.12.5-1","1.12.6-1","1.12.7-1","1.12.7-1ubuntu0.1","1.12.7-1ubuntu0.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"flatpak","binary_version":"1.12.7-1ubuntu0.1+esm1"},{"binary_version":"1.12.7-1ubuntu0.1+esm1","binary_name":"flatpak-tests"},{"binary_name":"gir1.2-flatpak-1.0","binary_version":"1.12.7-1ubuntu0.1+esm1"},{"binary_name":"libflatpak0","binary_version":"1.12.7-1ubuntu0.1+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-90616.json"}},{"package":{"name":"flatpak","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.14.4-2","1.14.5-1","1.14.5-1build1","1.14.5-1build4","1.14.5-1build5","1.14.5-1build6","1.14.6-1","1.14.6-1ubuntu0.1","1.14.6-1ubuntu0.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.14.6-1ubuntu0.1+esm1","binary_name":"flatpak"},{"binary_name":"flatpak-tests","binary_version":"1.14.6-1ubuntu0.1+esm1"},{"binary_name":"gir1.2-flatpak-1.0","binary_version":"1.14.6-1ubuntu0.1+esm1"},{"binary_version":"1.14.6-1ubuntu0.1+esm1","binary_name":"libflatpak0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-90616.json"}},{"package":{"name":"flatpak","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/flatpak?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.16.1-2ubuntu1","1.16.1-3ubuntu1","1.16.2-1","1.16.3-1","1.16.3-1build1","1.16.4-1","1.16.4-2","1.16.6-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.16.6-1","binary_name":"flatpak"},{"binary_name":"flatpak-tests","binary_version":"1.16.6-1"},{"binary_name":"gir1.2-flatpak-1.0","binary_version":"1.16.6-1"},{"binary_version":"1.16.6-1","binary_name":"libflatpak0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"Ubuntu","score":"medium"}]}