{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98982", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.384Z", "datePublished": "2026-10-23T12:19:59.784Z", "dateUpdated": "2026-10-23T12:19:59.784Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-23T12:19:59.784Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnamespace: don't let a pseudo dentry become the root of a mount\n\nd_alloc_pseudo() hands out dentries for pipes, sockets and other files\nthat are never anyone's child or parent. They carry DCACHE_NORCU and\ndentry_free() frees them right away because no lockless path walk can\never reach them. That holds as long as such a dentry isn't the root of\na mount. But bind mounting /proc/self/fd/<fd> of such a file does\nexactly that.\n\nMost callers of alloc_file_pseudo() put their files on kernel-internal\nmounts and may_copy_tree() refuses those. bpf_token_create() doesn't. It\nplaces the token file on the bpffs mount the caller handed it and that\nmount is in the caller's mount namespace so the clone goes through:\n\n mount --bind /proc/self/fd/<token> <file>\n open_tree(tokfd, \"\", AT_EMPTY_PATH | OPEN_TREE_CLONE) + move_mount()\n\n__follow_mount_rcu() then loads ->mnt_root of that mount, reads d_seq\nand d_flags of the dentry and only then checks mount_lock. The dentry\ncan be gone by then. The final mntput() of an unmounted parent unhooks\na child that stayed attached to it under mount_lock alone. When the\nchild's holder does the final put right after that the root is dput()\nand freed immediately while a walker that found the mount hashed still\nlooks at it.\n\nRefuse to clone a mount with a DCACHE_NORCU dentry as its root. Nothing\nsensible can be done with a bind mount of a bpf token anyway."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/namespace.c"], "versions": [{"version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "lessThan": "a256e31e0c54c4c37d2523aa52faabdcdd2ebc07", "status": "affected", "versionType": "git"}, {"version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "lessThan": "7e1c466011ba9e64d43075396badc03191bcee44", "status": "affected", "versionType": "git"}, {"version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "lessThan": "00287afa7cd989efdbf5822b7efac33cce7d489a", "status": "affected", "versionType": "git"}, {"version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "lessThan": "b138e16fb1e81376cea89f727dda7bfccd140de4", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/namespace.c"], "versions": [{"version": "6.9", "status": "affected"}, {"version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.113", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.11", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.12.113"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.57"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.2.11"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a256e31e0c54c4c37d2523aa52faabdcdd2ebc07"}, {"url": "https://git.kernel.org/stable/c/7e1c466011ba9e64d43075396badc03191bcee44"}, {"url": "https://git.kernel.org/stable/c/00287afa7cd989efdbf5822b7efac33cce7d489a"}, {"url": "https://git.kernel.org/stable/c/b138e16fb1e81376cea89f727dda7bfccd140de4"}], "title": "namespace: don't let a pseudo dentry become the root of a mount", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/namespace.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "a256e31e0c54c4c37d2523aa52faabdcdd2ebc07", "status": "affected", "version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "versionType": "git"}, {"lessThan": "7e1c466011ba9e64d43075396badc03191bcee44", "status": "affected", "version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "versionType": "git"}, {"lessThan": "00287afa7cd989efdbf5822b7efac33cce7d489a", "status": "affected", "version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "versionType": "git"}, {"lessThan": "b138e16fb1e81376cea89f727dda7bfccd140de4", "status": "affected", "version": "35f96de04127d332a5c5e8a155d31f452f88c76d", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/namespace.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.9"}, {"lessThan": "6.9", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.113", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.57", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.11", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnamespace: don't let a pseudo dentry become the root of a mount\n\nd_alloc_pseudo() hands out dentries for pipes, sockets and other files\nthat are never anyone's child or parent. They carry DCACHE_NORCU and\ndentry_free() frees them right away because no lockless path walk can\never reach them. That holds as long as such a dentry isn't the root of\na mount. But bind mounting /proc/self/fd/<fd> of such a file does\nexactly that.\n\nMost callers of alloc_file_pseudo() put their files on kernel-internal\nmounts and may_copy_tree() refuses those. bpf_token_create() doesn't. It\nplaces the token file on the bpffs mount the caller handed it and that\nmount is in the caller's mount namespace so the clone goes through:\n\n mount --bind /proc/self/fd/<token> <file>\n open_tree(tokfd, \"\", AT_EMPTY_PATH | OPEN_TREE_CLONE) + move_mount()\n\n__follow_mount_rcu() then loads ->mnt_root of that mount, reads d_seq\nand d_flags of the dentry and only then checks mount_lock. The dentry\ncan be gone by then. The final mntput() of an unmounted parent unhooks\na child that stayed attached to it under mount_lock alone. When the\nchild's holder does the final put right after that the root is dput()\nand freed immediately while a walker that found the mount hashed still\nlooks at it.\n\nRefuse to clone a mount with a DCACHE_NORCU dentry as its root. Nothing\nsensible can be done with a bind mount of a bpf token anyway."}], "id": "CVE-2026-98982", "lastModified": "2026-10-23T13:17:20.043", "metrics": {}, "published": "2026-10-23T13:17:20.043", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/00287afa7cd989efdbf5822b7efac33cce7d489a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7e1c466011ba9e64d43075396badc03191bcee44"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a256e31e0c54c4c37d2523aa52faabdcdd2ebc07"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b138e16fb1e81376cea89f727dda7bfccd140de4"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}