CVE-2025-71159

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-71159", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:30:19.665Z", "datePublished": "2026-01-23T15:23:57.824Z", "dateUpdated": "2026-08-05T12:12:25.188Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:12:25.188Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix use-after-free warning in btrfs_get_or_create_delayed_node()\n\nPreviously, btrfs_get_or_create_delayed_node() set the delayed_node's\nrefcount before acquiring the root->delayed_nodes lock.\nCommit e8513c012de7 (\"btrfs: implement ref_tracker for delayed_nodes\")\nmoved refcount_set inside the critical section, which means there is\nno longer a memory barrier between setting the refcount and setting\nbtrfs_inode->delayed_node.\n\nWithout that barrier, the stores to node->refs and\nbtrfs_inode->delayed_node may become visible out of order. Another\nthread can then read btrfs_inode->delayed_node and attempt to\nincrement a refcount that hasn't been set yet, leading to a\nrefcounting bug and a use-after-free warning.\n\nThe fix is to move refcount_set back to where it was to take\nadvantage of the implicit memory barrier provided by lock\nacquisition.\n\nBecause the allocations now happen outside of the lock's critical\nsection, they can use GFP_NOFS instead of GFP_ATOMIC."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - A remote attacker can reach the path through a writable Btrfs-backed ksmbd guest share: SMB2 WRITE reaches ksmbd_vfs_write(), kernel_write(), and the Btrfs ordered-write completion path. This is a reasonable network-facing Btrfs deployment.\nAC:L - Concurrent writes create multiple ordered extents whose parallel end-I/O workers can race while publishing and acquiring the same delayed node. The attacker controls the workload and can repeatedly create both sides of the race.\nPR:N - Although ksmbd checks the session, writable tree connection, and file handle, a guest-writable share grants these without attacker credentials. No prior account, capability, or local privilege is therefore required in that deployment.\nUI:N - The attacker directly triggers the race with concurrent write requests; no separate victim action is required.\nS:U - The vulnerable Btrfs code and the resulting kernel memory corruption are within the same host-kernel security authority.\nC:H - The lost reference can leave a delayed-node pointer usable after its slab object is freed and reused. Exploitation of this kernel use-after-free can expose arbitrary kernel memory.\nI:H - Subsequent mutex, flag, counter, tree, and inode-item operations write through the stale pointer. Heap reuse and spraying can turn these writes into kernel memory corruption and potential code execution.\nA:H - The observed refcount failure raises a kernel warning, and use of the prematurely freed delayed node can cause an oops, panic, hang, or filesystem shutdown."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/btrfs/delayed-inode.c"], "versions": [{"version": "e8513c012de75fd65e2df5499572bc6ef3f6e409", "lessThan": "c8385851a5435f4006281828d428e5d0b0bbf8af", "status": "affected", "versionType": "git"}, {"version": "e8513c012de75fd65e2df5499572bc6ef3f6e409", "lessThan": "83f59076a1ae6f5c6845d6f7ed3a1a373d883684", "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/btrfs/delayed-inode.c"], "versions": [{"version": "6.18", "status": "affected"}, {"version": "0", "lessThan": "6.18", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.6", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19", "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": "6.18", "versionEndExcluding": "6.18.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.19"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/c8385851a5435f4006281828d428e5d0b0bbf8af"}, {"url": "https://git.kernel.org/stable/c/83f59076a1ae6f5c6845d6f7ed3a1a373d883684"}], "title": "btrfs: fix use-after-free warning in btrfs_get_or_create_delayed_node()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/btrfs/delayed-inode.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "c8385851a5435f4006281828d428e5d0b0bbf8af", "status": "affected", "version": "e8513c012de75fd65e2df5499572bc6ef3f6e409", "versionType": "git"}, {"lessThan": "83f59076a1ae6f5c6845d6f7ed3a1a373d883684", "status": "affected", "version": "e8513c012de75fd65e2df5499572bc6ef3f6e409", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/btrfs/delayed-inode.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.18"}, {"lessThan": "6.18", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.19", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "B263F4AD-C03D-4E6A-995E-B822989C3A7A", "versionEndExcluding": "6.18.6", "versionStartIncluding": "6.18", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*", "matchCriteriaId": "17B67AA7-40D6-4AFA-8459-F200F3D7CFD1", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*", "matchCriteriaId": "C47E4CC9-C826-4FA9-B014-7FE3D9B318B2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*", "matchCriteriaId": "F71D92C0-C023-48BD-B3B6-70B638EEE298", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*", "matchCriteriaId": "13580667-0A98-40CC-B29F-D12790B91BDB", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix use-after-free warning in btrfs_get_or_create_delayed_node()\n\nPreviously, btrfs_get_or_create_delayed_node() set the delayed_node's\nrefcount before acquiring the root->delayed_nodes lock.\nCommit e8513c012de7 (\"btrfs: implement ref_tracker for delayed_nodes\")\nmoved refcount_set inside the critical section, which means there is\nno longer a memory barrier between setting the refcount and setting\nbtrfs_inode->delayed_node.\n\nWithout that barrier, the stores to node->refs and\nbtrfs_inode->delayed_node may become visible out of order. Another\nthread can then read btrfs_inode->delayed_node and attempt to\nincrement a refcount that hasn't been set yet, leading to a\nrefcounting bug and a use-after-free warning.\n\nThe fix is to move refcount_set back to where it was to take\nadvantage of the implicit memory barrier provided by lock\nacquisition.\n\nBecause the allocations now happen outside of the lock's critical\nsection, they can use GFP_NOFS instead of GFP_ATOMIC."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nbtrfs: soluciona la advertencia de uso despu\u00e9s de liberaci\u00f3n en btrfs_get_or_create_delayed_node()\n\nAnteriormente, btrfs_get_or_create_delayed_node() establec\u00eda el refcount del delayed_node antes de adquirir el bloqueo root->delayed_nodes. El commit e8513c012de7 ('btrfs: implementa ref_tracker para delayed_nodes') movi\u00f3 refcount_set dentro de la secci\u00f3n cr\u00edtica, lo que significa que ya no hay una barrera de memoria entre el establecimiento del refcount y el establecimiento de btrfs_inode->delayed_node.\n\nSin esa barrera, los almacenamientos en node->refs y btrfs_inode->delayed_node pueden volverse visibles fuera de orden. Otro hilo puede entonces leer btrfs_inode->delayed_node e intentar incrementar un refcount que a\u00fan no ha sido establecido, lo que lleva a un error de refcounting y a una advertencia de uso despu\u00e9s de liberaci\u00f3n.\n\nLa soluci\u00f3n es mover refcount_set de vuelta a donde estaba para aprovechar la barrera de memoria impl\u00edcita proporcionada por la adquisici\u00f3n del bloqueo.\n\nDebido a que las asignaciones ahora ocurren fuera de la secci\u00f3n cr\u00edtica del bloqueo, pueden usar GFP_NOFS en lugar de GFP_ATOMIC."}], "id": "CVE-2025-71159", "lastModified": "2026-07-30T06:24:54.993", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"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": "nvd@nist.gov", "type": "Primary"}]}, "published": "2026-01-23T16:15:52.793", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/83f59076a1ae6f5c6845d6f7ed3a1a373d883684"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/c8385851a5435f4006281828d428e5d0b0bbf8af"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: btrfs: fix use-after-free warning in btrfs_get_or_create_delayed_node()", "id": "2432378", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2432378"}, "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"}, "details": ["No description is available for this CVE."], "name": "CVE-2025-71159", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "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": "Not affected", "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"}], "public_date": "2026-01-23T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-71159\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-71159\nhttps://lore.kernel.org/linux-cve-announce/2026012346-CVE-2025-71159-417a@gregkh/T"], "threat_severity": "Low"}

{}