{"id":"CVE-2018-18955","state":"PUBLISHED","title":"In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more t","description":"In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction.","publishedAt":"2018-11-16T20:00:00.000Z","updatedAt":"2024-08-05T11:23:08.917Z","severity":null,"assigner":"mitre","products":["n/a n/a"],"affected":[{"vendor":"n/a","product":"n/a","versions":[{"version":"n/a","status":"affected"}]}],"references":["https://github.com/torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd","https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19","https://usn.ubuntu.com/3836-2/","https://usn.ubuntu.com/3835-1/","https://bugs.chromium.org/p/project-zero/issues/detail?id=1712","http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd","https://usn.ubuntu.com/3833-1/","https://usn.ubuntu.com/3832-1/","https://www.exploit-db.com/exploits/45915/","https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2","https://www.exploit-db.com/exploits/45886/","https://usn.ubuntu.com/3836-1/","http://www.securityfocus.com/bid/105941","https://support.f5.com/csp/article/K39103040","https://security.netapp.com/advisory/ntap-20190416-0003/"],"weaknesses":[],"ingestedAt":"2026-10-29T19:44:30.448Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2018/18xxx/CVE-2018-18955.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2018-18955","state":"PUBLISHED","datePublished":"2018-11-16T20:00:00.000Z","dateUpdated":"2024-08-05T11:23:08.917Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2018-11-05T00:00:00.000Z"},"containers":{"cna":{"descriptions":[{"lang":"en","value":"In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. 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