{"schemaVersion":3,"id":"CVE-2020-27837","aliases":["UBUNTU-CVE-2020-27837","DEBIAN-CVE-2020-27837"],"status":"published","duplicateOf":null,"title":null,"description":"A flaw was found in GDM in versions prior to 3.38.2.1. A race condition in the handling of session shutdown makes it possible to bypass the lock screen for a user that has autologin enabled, accessing their session without authentication. This is similar to CVE-2017-12164, but requires more difficult conditions to exploit.","dates":{"published":"2020-12-28T18:34:04.000Z","modified":"2024-08-04T16:25:43.322Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.4,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:P/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":"OSV · Ubuntu","score":6.4,"severity":"medium","vector":"CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","exploitability":1.3,"impact":9.8,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":6.4,"severity":"medium","vector":"CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","exploitability":1.3,"impact":9.8,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":6.4,"severity":"medium","vector":"CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":4.4,"severity":"medium","vector":"AV:L/AC:M/Au:N/C:P/I:P/A:P","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00228,"percentile":0.12741,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":0.003000000000000008,"baselineDate":"2026-09-20T00:00:00.000Z","baselineScore":0.00225},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00228,"percentile":0.12741}],"last30":[{"date":"2026-09-20T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00225,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00228,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00228,"percentile":0.12741}]},"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-362","name":"Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')","description":"The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.","type":"weakness","status":"Draft","abstraction":"Class","likelihoodOfExploit":"Medium","url":"https://cwe.mitre.org/data/definitions/362.html"}],"affected":[{"vendor":"debian","product":"gdm3","name":"gdm3","label":"gdm3","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/gdm3","purlType":"deb","versions":[{"text":"< 3.38.2.1-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 3.38.2.1-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"gdm3","name":"gdm3","label":"gdm3","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/gdm3","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"gnome","product":"gnome_display_manager","name":"gnome display manager","label":"gnome_display_manager","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 3.38.2.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 3.38.2.1","eol":null,"hubHref":"/vendor/gnome/gnome_display_manager"}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=1906812","label":"bugzilla.redhat.com/show_bug.cgi?id=1906812","hostname":"bugzilla.redhat.com","tags":["X Refsource MISC","Issue Tracking","Patch","Third Party Advisory"]},{"url":"https://ubuntu.com/security/CVE-2020-27837","label":"ubuntu.com/security/CVE-2020-27837","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2020-27837","label":"www.cve.org/CVERecord?id=CVE-2020-27837","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2020-27837","label":"security-tracker.debian.org/tracker/CVE-2020-27837","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["OPENSUSE-SU-2024:11547-1"],"duplicates":[],"related":["OPENSUSE-SU-2024:11547-1"]},"timeline":[{"kind":"published","date":"2020-12-28T18:34:04.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-08-04T16:25:43.322Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":26,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T00:33:40.838Z","stale":false,"partial":false}}