{"schemaVersion":3,"id":"CVE-2026-96281","aliases":["UBUNTU-CVE-2026-96281","DEBIAN-CVE-2026-96281"],"status":"published","duplicateOf":null,"title":null,"description":"On a multi-user system, a user with an active local login session could downgrade a system-wide Flatpak app to an older version by removing the app's remote ref via the unprivileged system-helper RemoveLocalRef method, causing the anti-downgrade check to fail to find a reference date. A malicious local user could use this to expose other users of the same system to an app version with unfixed vulnerabilities.","dates":{"published":"2026-09-27T21:00:17.262Z","modified":"2026-09-30T20:11:12.558Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.2,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:P/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":6.2,"severity":"medium","vector":"CVSS:3.1/AV:P/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":6.2,"severity":"medium","vector":"CVSS:3.1/AV:P/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H","exploitability":0.8,"impact":9.8,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":6.2,"severity":"medium","vector":"CVSS:3.1/AV:P/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H","exploitability":0.8,"impact":9.8,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":6.2,"severity":"medium","vector":"CVSS:3.1/AV:P/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00173,"percentile":0.0638,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-09-28T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00173,"percentile":0.0638}],"last30":[{"date":"2026-09-28T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00173,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00173,"percentile":0.0638}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-284","name":"Improper Access Control","description":"The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.","type":"weakness","status":"Incomplete","abstraction":"Pillar","likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/284.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~deb13u2","noFixRecorded":false,"fixedIn":null},{"text":"< 1.18.1-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 1.16.6-1~deb13u2 | < 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}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-96281","label":"access.redhat.com/security/cve/CVE-2026-96281","hostname":"access.redhat.com","tags":["VDB Entry","X Refsource REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2539421","label":"bugzilla.redhat.com/show_bug.cgi?id=2539421","hostname":"bugzilla.redhat.com","tags":["Issue Tracking","X Refsource REDHAT"]},{"url":"https://github.com/flatpak/flatpak/security/advisories/GHSA-q4gr-vc25-57m5","label":"github.com/flatpak/flatpak/security/advisories/GHSA-q4gr-vc25-57m5","hostname":"github.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-96281","label":"ubuntu.com/security/CVE-2026-96281","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-96281","label":"www.cve.org/CVERecord?id=CVE-2026-96281","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-96281","label":"security-tracker.debian.org/tracker/CVE-2026-96281","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["SUSE-SU-2026:4610-1"],"duplicates":[],"related":["SUSE-SU-2026:4610-1"]},"timeline":[{"kind":"published","date":"2026-09-27T21:00:17.262Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-09-30T20:11:12.558Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":25,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-22T11:56:17.696Z","stale":false,"partial":false}}