CVE-2026-98982

{"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": "2026-10-24T14:09:50.745Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-24T14:09:50.745Z"}, "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."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - Local bpf(BPF_TOKEN_CREATE) reaches bpf_token_create()/alloc_file_pseudo(), after which mount(MS_BIND) or open_tree(OPEN_TREE_CLONE) reaches the patched __do_loopback() on /proc/self/fd/<token>; no network protocol carries the triggering data.\nAC:L - The attacker controls creation and teardown of the token-root mount and can race cleanup_mnt()/dput() against openat() reaching __follow_mount_rcu() using concurrent threads; neither side of the race requires external timing or victim-controlled state.\nPR:L - bpf_token_create() requires CAP_BPF in the bpffs user namespace, while open_tree(OPEN_TREE_CLONE) and move_mount() require CAP_SYS_ADMIN over the mount namespace; because bpf_fs_type has FS_USERNS_MOUNT, an ordinary user can obtain these capabilities through unprivileged user and mount namespaces.\nUI:N - The attacking process performs every required action itself: mounting delegated bpffs, creating the token, cloning and tearing down mounts, and racing openat(); no victim must mount, open, or otherwise process attacker-supplied data.\nS:U - The freed dentry is consumed by __follow_mount_rcu() inside the same host kernel, yielding ordinary local kernel compromise or denial of service rather than crossing a VM, IOMMU, or separate security-authority boundary.\nC:H - cleanup_mnt() can dput() and immediately free the DCACHE_NORCU mount root while __follow_mount_rcu() still reads its d_seq, d_flags, and potentially d_op; attacker-driven dentry-cache reuse makes this kernel UAF capable of high-impact memory disclosure.\nI:H - The freed struct dentry can be reclaimed through attacker-driven dentry allocation, letting heap spraying influence fields and the d_op->d_manage dispatch consumed by __follow_mount_rcu(); this is an exploitable kernel UAF path to arbitrary modification or control-flow hijacking.\nA:H - __follow_mount_rcu() dereferences the mount root after dentry_free() has returned it immediately to dentry_cache, so poisoned or reclaimed contents can cause a kernel oops or panic, and attacker-controlled threads can repeat the race."}]}], "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": "2026-10-24T14:16:50.850", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "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"}

{"bugzilla": {"description": "kernel: namespace: don't let a pseudo dentry become the root of a mount", "id": "2559751", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2559751"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nnamespace: don't let a pseudo dentry become the root of a mount\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.\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:\nmount --bind /proc/self/fd/<token> <file>\nopen_tree(tokfd, \"\", AT_EMPTY_PATH | OPEN_TREE_CLONE) + move_mount()\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.\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.", "A flaw was found in the Linux kernel. A local user could exploit a use-after-free vulnerability to cause a Denial of Service (DoS) or potentially escalate privileges on the system. By bind-mounting a pseudo file descriptor, such as a Berkeley Packet Filter (BPF) token, as the root of a mount point, the kernel bypasses normal memory reclamation delays when releasing directory entries. Consequently, concurrent path lookup operations can access freed memory, resulting in memory corruption and a system crash."], "name": "CVE-2026-98982", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-23T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-98982\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98982\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98982.mbox"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,a256e31e0c54c4c37d2523aa52faabdcdd2ebc07)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,7e1c466011ba9e64d43075396badc03191bcee44)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,00287afa7cd989efdbf5822b7efac33cce7d489a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,b138e16fb1e81376cea89f727dda7bfccd140de4)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.9"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.9)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.113,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.57,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.11,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,a256e31e0c54c4c37d2523aa52faabdcdd2ebc07)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,7e1c466011ba9e64d43075396badc03191bcee44)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,00287afa7cd989efdbf5822b7efac33cce7d489a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[35f96de04127d332a5c5e8a155d31f452f88c76d,b138e16fb1e81376cea89f727dda7bfccd140de4)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.9"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.9)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.113,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.57,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.11,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-23T15:00:13.038825+00:00", "updated": "2026-10-29T22:00:09.200986+00:00", "vendors": ["linux", "linux$PRODUCT$linux", "linux$PRODUCT$linux_kernel"]}