{"id":"UBUNTU-CVE-2021-20254","details":"A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.","modified":"2026-04-22T14:32:10.575021Z","published":"2021-04-29T00:00:00Z","related":["USN-4930-1","USN-4931-1"],"upstream":["CVE-2021-20254"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-20254"},{"type":"REPORT","url":"https://www.samba.org/samba/security/CVE-2021-20254.html"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4930-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4931-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-20254"}],"affected":[{"package":{"name":"samba","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/samba@2:4.3.11+dfsg-0ubuntu0.14.04.20+esm11?arch=source&distro=trusty/esm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:4.3.11+dfsg-0ubuntu0.14.04.20+esm11"}]}],"versions":["2:3.6.18-1ubuntu3","2:4.0.10+dfsg-4ubuntu2","2:4.0.13+dfsg-1ubuntu1","2:4.1.3+dfsg-2ubuntu2","2:4.1.3+dfsg-2ubuntu3","2:4.1.3+dfsg-2ubuntu4","2:4.1.3+dfsg-2ubuntu5","2:4.1.6+dfsg-1ubuntu1","2:4.1.6+dfsg-1ubuntu2","2:4.1.6+dfsg-1ubuntu2.14.04.1","2:4.1.6+dfsg-1ubuntu2.14.04.2","2:4.1.6+dfsg-1ubuntu2.14.04.3","2:4.1.6+dfsg-1ubuntu2.14.04.4","2:4.1.6+dfsg-1ubuntu2.14.04.5","2:4.1.6+dfsg-1ubuntu2.14.04.7","2:4.1.6+dfsg-1ubuntu2.14.04.8","2:4.1.6+dfsg-1ubuntu2.14.04.9","2:4.1.6+dfsg-1ubuntu2.14.04.11","2:4.1.6+dfsg-1ubuntu2.14.04.12","2:4.1.6+dfsg-1ubuntu2.14.04.13","2:4.3.8+dfsg-0ubuntu0.14.04.2","2:4.3.9+dfsg-0ubuntu0.14.04.1","2:4.3.9+dfsg-0ubuntu0.14.04.3","2:4.3.11+dfsg-0ubuntu0.14.04.1","2:4.3.11+dfsg-0ubuntu0.14.04.2","2:4.3.11+dfsg-0ubuntu0.14.04.3","2:4.3.11+dfsg-0ubuntu0.14.04.4","2:4.3.11+dfsg-0ubuntu0.14.04.6","2:4.3.11+dfsg-0ubuntu0.14.04.7","2:4.3.11+dfsg-0ubuntu0.14.04.8","2:4.3.11+dfsg-0ubuntu0.14.04.9","2:4.3.11+dfsg-0ubuntu0.14.04.10","2:4.3.11+dfsg-0ubuntu0.14.04.11","2:4.3.11+dfsg-0ubuntu0.14.04.12","2:4.3.11+dfsg-0ubuntu0.14.04.13","2:4.3.11+dfsg-0ubuntu0.14.04.14","2:4.3.11+dfsg-0ubuntu0.14.04.16","2:4.3.11+dfsg-0ubuntu0.14.04.17","2:4.3.11+dfsg-0ubuntu0.14.04.19","2:4.3.11+dfsg-0ubuntu0.14.04.20","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm1","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm2","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm3","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm4","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm6","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm7","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm8","2:4.3.11+dfsg-0ubuntu0.14.04.20+esm9"],"ecosystem_specific":{"availability":"Available 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