{"id":"CVE-2021-3995","details":"A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users who have a UID that is a prefix of the UID of the attacker in its string form. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.","modified":"2026-04-16T04:36:33.512970943Z","published":"2022-08-23T20:15:08.493Z","related":["SUSE-SU-2022:0727-1","SUSE-SU-2022:0727-2","openSUSE-SU-2022:0727-1","openSUSE-SU-2024:11784-1"],"references":[{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202401-08"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20221209-0002/"},{"type":"ADVISORY","url":"http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html"},{"type":"ADVISORY","url":"http://seclists.org/fulldisclosure/2022/Dec/4"},{"type":"ADVISORY","url":"http://www.openwall.com/lists/oss-security/2022/11/30/2"},{"type":"ADVISORY","url":"https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2024631https://access.redhat.com/security/cve/CVE-2021-3995"},{"type":"FIX","url":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d"},{"type":"FIX","url":"https://www.openwall.com/lists/oss-security/2022/01/24/2"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/karelzak/util-linux","events":[{"introduced":"d4319b91c9d7d69e7b954fc66819214f81501312"},{"fixed":"331a1e6e10f7943a12112c7161a8c995c1c5b9b9"}],"database_specific":{"versions":[{"introduced":"2.34"},{"fixed":"2.37.3"}]}},{"type":"GIT","repo":"https://github.com/util-linux/util-linux","events":[{"introduced":"0"},{"fixed":"57202f5713afa2af20ffbb6ab5331481d0396f8d"}]}],"versions":["v2.10f","v2.10m","v2.10s","v2.11b","v2.11f","v2.11m","v2.11n","v2.11o","v2.11q","v2.11r","v2.11t","v2.11u","v2.11v","v2.11w","v2.11x","v2.11y","v2.12","v2.12a","v2.12b","v2.12d","v2.12h","v2.12i","v2.12j","v2.12k","v2.12l","v2.12m","v2.12o","v2.12p","v2.12pre","v2.12q","v2.12q-pre1","v2.12q-pre2","v2.12r","v2.12r-pre1","v2.13","v2.13-pre1","v2.13-pre2","v2.13-pre3","v2.13-pre4","v2.13-pre5","v2.13-pre6","v2.13-pre7","v2.13-rc1","v2.13-rc2","v2.13-rc3","v2.14","v2.14-rc1","v2.14-rc2","v2.14-rc3","v2.15","v2.15-rc1","v2.15-rc2","v2.16","v2.16-rc1","v2.16-rc2","v2.17","v2.17-rc1","v2.17-rc2","v2.17-rc3","v2.18","v2.18-rc1","v2.18-rc2","v2.19","v2.19-rc1","v2.19-rc2","v2.19-rc3","v2.2","v2.20","v2.20-rc1","v2.20-rc2","v2.21","v2.21-rc1","v2.21-rc2","v2.22","v2.22-rc1","v2.22-rc2","v2.23","v2.23-rc1","v2.23-rc2","v2.24","v2.24-rc1","v2.24-rc2","v2.25","v2.25-rc1","v2.25-rc2","v2.26","v2.26-rc1","v2.26-rc2","v2.27","v2.27-rc1","v2.27-rc2","v2.28","v2.28-rc1","v2.28-rc2","v2.29","v2.29-rc1","v2.29-rc2","v2.30","v2.30-rc1","v2.30-rc2","v2.31","v2.31-rc1","v2.31-rc2","v2.32","v2.32-rc1","v2.32-rc2","v2.33","v2.33-rc1","v2.33-rc2","v2.34","v2.34-rc1","v2.34-rc2","v2.35","v2.35-rc1","v2.35-rc2","v2.36","v2.36-rc1","v2.36-rc2","v2.37","v2.37-rc1","v2.37-rc2","v2.37.1","v2.37.2","v2.5","v2.7.1","v2.8","v2.9i","v2.9v"],"database_specific":{"vanir_signatures_modified":"2026-04-11T21:23:19Z","source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3995.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"last_affected":"35"}]}],"vanir_signatures":[{"target":{"file":"libmount/src/context_umount.c"},"signature_version":"v1","id":"CVE-2021-3995-1269fc08","source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d","signature_type":"Line","deprecated":false,"digest":{"line_hashes":["81833027147814142702493867864697118814","22792341624995426804440732716874906998","188129392422443153924944788904067990904","289832127756634622752234079428081538359","188233886253345268096733697169544595795","54138356629918355815573150655132355934","324292356523075565319494258265560506588","114881293640818590502704345181145763206","252555775388927122890851343390493895485","9508519970305665832091602711484130055","228804560706147985872816054995110662106","252883063391353887645273737182603475220","44534298722337665907700591885301216326","94670876492226503115421535655832914762","29640391338747571040081614814014233685","103760253877128533039879473059782134202","255531754742027994346867870546517870151","1246224938679420241439038734661924898"],"threshold":0.9}},{"target":{"file":"libmount/src/mountP.h"},"signature_version":"v1","id":"CVE-2021-3995-2ca3bb48","source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d","signature_type":"Line","deprecated":false,"digest":{"line_hashes":["272811208154020133914318975517155984077","216228617924098157011331334669078161763","114236596888292634881368870369009595218"],"threshold":0.9}},{"target":{"file":"libmount/src/context_umount.c","function":"is_fuse_usermount"},"signature_version":"v1","id":"CVE-2021-3995-74f6c434","source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d","signature_type":"Function","deprecated":false,"digest":{"length":908,"function_hash":"109824080416446340833412381312032531836"}},{"signature_version":"v1","target":{"file":"libmount/src/optstr.c"},"id":"CVE-2021-3995-a6de3fc7","source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d","signature_type":"Line","deprecated":false,"digest":{"line_hashes":["60879234107707746506513134776949747801","81822503343067849456986118838830635954","318274765580926732049416029184645580805"],"threshold":0.9}}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}