{"schemaVersion":3,"id":"CVE-2026-90616","aliases":["UBUNTU-CVE-2026-90616","DEBIAN-CVE-2026-90616"],"status":"published","duplicateOf":null,"title":null,"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.","dates":{"published":"2026-09-12T20:00:58.476Z","modified":"2026-09-14T18:22:31.917Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":7.4,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":7.4,"severity":"high","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":7.4,"severity":"high","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","exploitability":3.6,"impact":9.8,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · 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Symbolic Link (Symlink) Following","description":"The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.","type":"weakness","status":"Incomplete","abstraction":"Compound","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/61.html"}],"affected":[{"vendor":"debian","product":"flatpak","name":"flatpak","label":"flatpak","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/flatpak","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 1.16.6-1~deb13u3","noFixRecorded":false,"fixedIn":null},{"text":"< 1.18.1-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 1.16.6-1~deb13u3 | < 1.18.1-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"flatpak","name":"flatpak","label":"flatpak","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/flatpak","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"flatpak","product":"flatpak","name":"flatpak","label":"flatpak","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.18.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.18.1","eol":null,"hubHref":"/vendor/flatpak/flatpak"}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj","label":"github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj","hostname":"github.com","tags":["REPORT"]},{"url":"https://www.openwall.com/lists/oss-security/2026/08/11/9","label":"www.openwall.com/lists/oss-security/2026/08/11/9","hostname":"www.openwall.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-90616","label":"ubuntu.com/security/CVE-2026-90616","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90616","label":"www.cve.org/CVERecord?id=CVE-2026-90616","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-90616","label":"security-tracker.debian.org/tracker/CVE-2026-90616","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["MGASA-2026-0342","RHSA-2026:80497","RHSA-2026:80498","RHSA-2026:80687","SUSE-SU-2026:4610-1"],"duplicates":[],"related":["SUSE-SU-2026:4610-1"]},"timeline":[{"kind":"published","date":"2026-09-12T20:00:58.476Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-09-14T18:22:31.917Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":30,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T21:17:04.466Z","stale":false,"partial":false}}