{"id":"CVE-2026-98987","revision":null,"records":[{"revision":"554e1d867ca74c66a8c13532c22dc5bf","observedAt":"2026-10-23T16:01:20.601+00:00","statement":{"source":"cve-program","id":"CVE-2026-98987","aliases":[],"title":"namespace: look at the topmost mount for a mount namespace file","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnamespace: look at the topmost mount for a mount namespace file\n\nattach_recursive_mnt() preallocates a mountpoint for the root of the\ntopmost mount of the source so that a mount that already sits at the\ndestination can be put on top of the source or on top of one of its\npropagated copies.\n\nThe copies are made without CL_COPY_MNT_NS_FILE so their chain of\novermounts is shorter than the source's. It ends below the first bind\nmount of a mount namespace file. So while the loop walks up the chain of\nthe source it remembers the mountpoint of that mount in \"shorter\" and\nthe existing mount is put there for the copies.\n\nBut the loop ends at the topmost mount without ever looking at it. If\nthe topmost mount is the only mount namespace file in the chain\n\"shorter\" stays NULL and mnt_change_mountpoint() attaches the existing\nmount of the copy below the root of the mount namespace file. That's a\ndentry of nsfs. No path walk in the copy's mount namespace ever gets\nthere. The mount is gone until its parent goes and the copy that took\nits place can't be unmounted synchronously because it has a child:\n\n  S      bind mount of a file\n  N      bind mount of a mount namespace file on top of S\n  A      shared mount, B a slave of A, Q mounted on B/file\n\n  move_mount(S, A/file)\n  cat B/file          -> the content of S instead of Q\n  umount B/file       -> EBUSY\n\nLook at every mount of the chain including the topmost one.","state":0,"publishedAt":"2026-10-23T12:20:06.18+00:00","modifiedAt":"2026-10-23T12:20:06.18+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/namespace.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"96f5d2e051653f2cfe9137c5d3c7794c358ffb03\",\n                            \"lessThan\": \"b9c40553f6ceba50042281eef6f701e5fb719726\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"96f5d2e051653f2cfe9137c5d3c7794c358ffb03\",\n                            \"lessThan\": \"87ecd4c6da146363384a603bd9e90c90e7275536\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"96f5d2e051653f2cfe9137c5d3c7794c358ffb03\",\n                            \"lessThan\": \"8714b44adac7b10506e1db3ef1710689751f0f10\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/namespace.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.17\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.17\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.57\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.11\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/b9c40553f6ceba50042281eef6f701e5fb719726","https://git.kernel.org/stable/c/87ecd4c6da146363384a603bd9e90c90e7275536","https://git.kernel.org/stable/c/8714b44adac7b10506e1db3ef1710689751f0f10"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98987","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98987","identifiers":["CVE-2026-98987"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-10-28T03:51:33.9437802+00:00","complete":true,"records":1760,"lastAttemptAt":"2026-10-28T03:51:33.9437802+00:00","lastSuccessAt":"2026-10-28T03:51:34.0961236+00:00","error":null,"lastVerifiedAt":"2026-10-28T03:51:34.0961246+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-d2186f400c54d65f61687f78bb1a00d184d2e215877d0194d7ed70caee809a44-5e002664ec8433c1a0afdeba204aeae5ffbe828d6bbdb74ae37529eb2b6b1b6f","complete":true,"records":415510,"lastAttemptAt":"2026-10-28T03:51:32.842736+00:00","lastSuccessAt":"2026-10-28T03:51:32.8041674+00:00","error":null,"lastVerifiedAt":"2026-10-28T03:51:32.842736+00:00","snapshotPublishedAt":"2026-10-28T03:24:13+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-233b167da0484950a642d70fecbb2f8f","complete":false,"records":9694,"lastAttemptAt":"2026-10-28T04:03:09.0504101+00:00","lastSuccessAt":"2026-10-28T04:03:09.046+00:00","error":"18 identifier lookups failed; latest failures include HTTP 403. Other identifiers were checked independently.","lastVerifiedAt":"2026-10-28T04:03:09.046+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":4982,"expectedIdentifiers":13514,"failedIdentifiers":18},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-10-28T03:51:33.9437802+00:00","complete":true,"records":1093,"lastAttemptAt":"2026-10-28T03:51:33.9437802+00:00","lastSuccessAt":"2026-10-28T03:51:34.0971299+00:00","error":null,"lastVerifiedAt":"2026-10-28T03:51:34.09713+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-8d16a738328646698f9217d8ea11893c","complete":true,"records":13449,"lastAttemptAt":"2026-10-28T03:51:36.4785313+00:00","lastSuccessAt":"2026-10-27T22:48:29.491+00:00","error":null,"lastVerifiedAt":"2026-10-27T22:48:29.491+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13514,"expectedIdentifiers":13514,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-f7cb12508d9e6a348c8a60f772ed85529cc80cd2ff853da1099b57754b20e943","complete":true,"records":9790,"lastAttemptAt":"2026-10-28T03:51:33.4681471+00:00","lastSuccessAt":"2026-10-27T21:49:03.9756799+00:00","error":null,"lastVerifiedAt":"2026-10-28T03:51:33.4681471+00:00","snapshotPublishedAt":"2026-10-27T21:48:11+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-72e5e79de0026dd0562d40734074a2236a06886643d67182b8381eaee757dbf7","complete":true,"records":1966,"lastAttemptAt":"2026-10-28T03:51:32.8879793+00:00","lastSuccessAt":"2026-10-27T21:46:38.0277323+00:00","error":null,"lastVerifiedAt":"2026-10-28T03:51:32.8879793+00:00","snapshotPublishedAt":"2026-10-27T21:18:15+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-3a5b306d60fc44677a03a8afc99d87e6c5402770ef68d560f94a8c3ad3802b75","complete":true,"records":3001,"lastAttemptAt":"2026-10-28T03:51:33.8464162+00:00","lastSuccessAt":"2026-10-27T16:45:49.0050993+00:00","error":null,"lastVerifiedAt":"2026-10-28T03:51:33.8464162+00:00","snapshotPublishedAt":"2026-10-27T16:33:43+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-5f3141cf1b985319fe2c9d9b1b1aab03f442c3a2272590c3c2e44d5d3d31bfb3","complete":true,"records":230854,"lastAttemptAt":"2026-10-28T03:51:33.3608683+00:00","lastSuccessAt":"2026-10-28T02:53:16.9493663+00:00","error":null,"lastVerifiedAt":"2026-10-28T03:51:33.3608683+00:00","snapshotPublishedAt":"2026-10-28T02:33:06+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}