CVE-2025-40084

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-40084", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.161Z", "datePublished": "2025-10-29T13:37:03.185Z", "dateUpdated": "2026-08-05T12:07:38.947Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:07:38.947Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: transport_ipc: validate payload size before reading handle\n\nhandle_response() dereferences the payload as a 4-byte handle without\nverifying that the declared payload size is at least 4 bytes. A malformed\nor truncated message from ksmbd.mountd can lead to a 4-byte read past the\ndeclared payload size. Validate the size before dereferencing.\n\nThis is a minimal fix to guard the initial handle read."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable code is reached only via a generic netlink message to the `SMBD_GENL` family (`handle_generic_event` \u2192 `handle_response`), which requires a local socket on the machine; a remote SMB client on TCP/445 cannot inject IPC responses.\nAC:L - The attacker fully controls the crafted netlink message \u2014 a zero-length `KSMBD_EVENT_RPC_RESPONSE`/`SPNEGO_AUTHEN_RESPONSE` attribute followed by a chosen nlattr header supplies both the undersized `sz` and the out-of-bounds \"handle\" value, and IDA-allocated handles are small and brute-forceable.\nPR:L - The `netlink_capable(CAP_NET_ADMIN)` gate exists only when `CONFIG_SMB_SERVER_CHECK_CAP_NET_ADMIN` is set, and builds that disable it let any unprivileged local user open a `NETLINK_GENERIC` socket and send the message; there is also no check binding the sender to the registered `ksmbd_tools_pid`.\nUI:N - The attacker sends the malformed netlink message directly; no victim action is needed beyond ksmbd already running, which is the normal state on an SMB server.\nS:U - The out-of-bounds read and the resulting fault stay within the kernel's own security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The unchecked deref reads 4 bytes past the declared payload, and the undersized response it admits causes `ipc_validate_msg()` and the SPNEGO/RPC consumers to read fields beyond a tiny slab allocation, whose contents can be reflected back toward the SMB client.\nI:N - The `memcpy(entry->response, payload, sz)` is bounded by the same `sz` used for the allocation, so the bug yields no out-of-bounds write or other data-modification primitive.\nA:H - A zero-length payload makes `kvzalloc(0)` return `ZERO_SIZE_PTR`, which passes the non-NULL check and is then dereferenced in `ipc_validate_msg()`, producing a kernel oops that is repeatable at will."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/transport_ipc.c"], "versions": [{"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "a02e432d5130da4c723aabe1205bac805889fdb2", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "2dc125f5da134c0915a840b62565c60a595673dd", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "898d527ed94c19980a4d848f10057f1fed578ffb", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "867ffd9d67285612da3f0498ca618297f8e41f01", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "6f40e50ceb99fc8ef37e5c56e2ec1d162733fef0", "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/smb/server/transport_ipc.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.158", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.115", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.56", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17.6", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18", "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": "5.15", "versionEndExcluding": "6.1.158"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.115"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.56"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.17.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a02e432d5130da4c723aabe1205bac805889fdb2"}, {"url": "https://git.kernel.org/stable/c/2dc125f5da134c0915a840b62565c60a595673dd"}, {"url": "https://git.kernel.org/stable/c/898d527ed94c19980a4d848f10057f1fed578ffb"}, {"url": "https://git.kernel.org/stable/c/867ffd9d67285612da3f0498ca618297f8e41f01"}, {"url": "https://git.kernel.org/stable/c/6f40e50ceb99fc8ef37e5c56e2ec1d162733fef0"}], "title": "ksmbd: transport_ipc: validate payload size before reading handle", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/server/transport_ipc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "a02e432d5130da4c723aabe1205bac805889fdb2", "status": "affected", "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "versionType": "git"}, {"lessThan": "2dc125f5da134c0915a840b62565c60a595673dd", "status": "affected", "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "versionType": "git"}, {"lessThan": "898d527ed94c19980a4d848f10057f1fed578ffb", "status": "affected", "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "versionType": "git"}, {"lessThan": "867ffd9d67285612da3f0498ca618297f8e41f01", "status": "affected", "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "versionType": "git"}, {"lessThan": "6f40e50ceb99fc8ef37e5c56e2ec1d162733fef0", "status": "affected", "version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/server/transport_ipc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.15"}, {"lessThan": "5.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.158", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.115", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.56", "versionType": "semver"}, {"lessThanOrEqual": "6.17.*", "status": "unaffected", "version": "6.17.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.18", "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\nksmbd: transport_ipc: validate payload size before reading handle\n\nhandle_response() dereferences the payload as a 4-byte handle without\nverifying that the declared payload size is at least 4 bytes. A malformed\nor truncated message from ksmbd.mountd can lead to a 4-byte read past the\ndeclared payload size. Validate the size before dereferencing.\n\nThis is a minimal fix to guard the initial handle read."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:\n\nksmbd: transport_ipc: validar el tama\u00f1o de la carga \u00fatil antes de leer el handle\n\nhandle_response() desreferencia la carga \u00fatil como un handle de 4 bytes sin verificar que el tama\u00f1o de la carga \u00fatil declarado sea de al menos 4 bytes. Un mensaje malformado o truncado de ksmbd.mountd puede provocar una lectura de 4 bytes m\u00e1s all\u00e1 del tama\u00f1o de la carga \u00fatil declarado. Validar el tama\u00f1o antes de desreferenciar.\n\nEsta es una correcci\u00f3n m\u00ednima para proteger la lectura inicial del handle."}], "id": "CVE-2025-40084", "lastModified": "2026-10-19T21:10:00.160", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2025-10-29T14:15:55.007", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2dc125f5da134c0915a840b62565c60a595673dd"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6f40e50ceb99fc8ef37e5c56e2ec1d162733fef0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/867ffd9d67285612da3f0498ca618297f8e41f01"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/898d527ed94c19980a4d848f10057f1fed578ffb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a02e432d5130da4c723aabe1205bac805889fdb2"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Deferred"}

{"bugzilla": {"description": "kernel: ksmbd: transport_ipc: validate payload size before reading handle", "id": "2407085", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2407085"}, "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-2025-40084", "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": "Not affected", "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": "2025-10-29T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-40084\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-40084\nhttps://lore.kernel.org/linux-cve-announce/2025102909-CVE-2025-40084-1407@gregkh/T"], "threat_severity": "Moderate"}

{"created": "2025-10-30T14:38:24.632057+00:00", "updated": "2025-10-30T14:38:24.632081+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}