{"id":"CVE-2026-90616","state":"PUBLISHED","title":"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,","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.","publishedAt":"2026-09-12T20:00:58.476Z","updatedAt":"2026-09-14T18:22:31.917Z","severity":{"score":7.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"mitre"},"assigner":"mitre","products":["Flatpak Flatpak"],"affected":[{"vendor":"Flatpak","product":"Flatpak","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.18.1","versionType":"semver"}],"platforms":["Linux"],"repo":"https://github.com/flatpak/flatpak"}],"references":["https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj","https://www.openwall.com/lists/oss-security/2026/08/11/9"],"weaknesses":["CWE-61"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90616.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90616","state":"PUBLISHED","datePublished":"2026-09-12T20:00:58.476Z","dateUpdated":"2026-09-14T18:22:31.917Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2026-09-12T20:00:58.046Z"},"containers":{"cna":{"descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Flatpak","product":"Flatpak","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.18.1","versionType":"semver"}],"platforms":["Linux"],"repo":"https://github.com/flatpak/flatpak"}],"references":[{"url":"https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj"},{"url":"https://www.openwall.com/lists/oss-security/2026/08/11/9"}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":7.4,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-61","description":"CWE-61 UNIX Symbolic Link (Symlink) Following","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"mitre","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateUpdated":"2026-09-12T20:00:58.476Z"},"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https://github.com/flatpak/flatpak/commit/478072972056d2d15c768c246f80abdf83cf0e5e\">https://github.com/flatpak/flatpak/commit/478072972056d2d15c768c246f80abdf83cf0e5e</a><br>"}],"value":"https://github.com/flatpak/flatpak/commit/478072972056d2d15c768c246f80abdf83cf0e5e"}],"x_generator":{"engine":"CVE-Request-form 0.0.1"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:flatpak:flatpak:*:*:*:*:*:*:*:*","versionEndExcluding":"1.18.1"}]}]}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-14T18:22:12.062132Z","id":"CVE-2026-90616","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-14T18:22:31.917Z"}}]}}}