{"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":"2026-07-09T00:36:41.672808Z","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"],"database_specific":{"unresolved_ranges":[{"cpes":["cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*"],"extracted_events":[{"introduced":"35"},{"last_affected":"35"}],"source":"CPE_STRING","vendor_product":"fedoraproject:fedora"}]},"references":[{"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":"ADVISORY","url":"https://security.gentoo.org/glsa/202401-08"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20221209-0002/"},{"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/util-linux/util-linux","events":[{"introduced":"d4319b91c9d7d69e7b954fc66819214f81501312"},{"fixed":"331a1e6e10f7943a12112c7161a8c995c1c5b9b9"},{"fixed":"57202f5713afa2af20ffbb6ab5331481d0396f8d"}],"database_specific":{"extracted_events":[{"introduced":"2.34"},{"fixed":"2.37.3"}],"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*"}}],"versions":["v2.37.2","v2.37.1","v2.37","v2.37-rc2","v2.37-rc1","v2.36","v2.36-rc2","v2.36-rc1","v2.35","v2.35-rc2","v2.35-rc1","v2.34"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3995.json","vanir_signatures_modified":"2026-07-09T00:36:41Z","vanir_signatures":[{"target":{"file":"libmount/src/context_umount.c"},"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},"id":"CVE-2021-3995-1269fc08","signature_type":"Line","signature_version":"v1","source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d"},{"source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d","target":{"file":"libmount/src/mountP.h"},"deprecated":false,"digest":{"line_hashes":["272811208154020133914318975517155984077","216228617924098157011331334669078161763","114236596888292634881368870369009595218"],"threshold":0.9},"id":"CVE-2021-3995-2ca3bb48","signature_type":"Line","signature_version":"v1"},{"digest":{"function_hash":"109824080416446340833412381312032531836","length":908},"id":"CVE-2021-3995-74f6c434","signature_type":"Function","signature_version":"v1","source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d","target":{"file":"libmount/src/context_umount.c","function":"is_fuse_usermount"},"deprecated":false},{"deprecated":false,"digest":{"line_hashes":["60879234107707746506513134776949747801","81822503343067849456986118838830635954","318274765580926732049416029184645580805"],"threshold":0.9},"id":"CVE-2021-3995-a6de3fc7","signature_type":"Line","signature_version":"v1","source":"https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d","target":{"file":"libmount/src/optstr.c"}}]}}],"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"}]}