CVE-2023-3866

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So work->sess and work->tcon could be NULL.\nIf secound request in the compound access work->sess or tcon, It cause\nNULL pointer dereferecing error."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - The vulnerable code is in ksmbd (fs/smb/server/), the in-kernel SMB server reachable over TCP/445; a remote attacker triggers it by sending a crafted compound SMB2 request to a listening ksmbd instance.\nAC:L - The attacker fully controls the compound PDU layout and can reliably place SMB2_ECHO (or NEGOTIATE/SESSION_SETUP) first so session/tree validation is skipped for subsequent commands; no race or attacker-uncontrollable condition is required.\nPR:N - SMB2_ECHO/NEGOTIATE/SESSION_SETUP bypass smb2_check_user_session() without credentials, and with work->sess left NULL signing checks are also skipped, so the crash path is reachable pre-authentication over the network.\nUI:N - Exploitation requires only attacker-sent SMB2 compound packets to an already-running ksmbd listener; no victim user or administrator action is needed.\nS:U - Impact is confined to the host kernel/ksmbd security authority (kernel oops/DoS on the SMB server host); this is not a VM escape, IOMMU bypass, or other cross-authority boundary change.\nC:N - The defect is a pure NULL pointer dereference (e.g. tcon->share_conf with tcon NULL in smb2_open); it does not provide an information-disclosure or arbitrary-read primitive.\nI:N - The bug yields a NULL dereference crash rather than an out-of-bounds write, UAF, or other integrity/control-flow corruption primitive.\nA:H - Subsequent compound commands dereference NULL session/tree pointers, causing a kernel oops that an unauthenticated remote attacker can retrigger at will, denying service to ksmbd and potentially the host."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/server.c", "fs/smb/server/smb2pdu.c"], "versions": [{"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "eb947403518ea3d93f6d89264bb1f5416bb0c7d0", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "854156d12caa9d36de1cf5f084591c7686cc8a9d", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "d1066c1b3663401cd23c0d6e60cdae750ce00c0f", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "5005bcb4219156f1bf7587b185080ec1da08518e", "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/server.c", "fs/smb/server/smb2pdu.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.121", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.36", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.3.10", "lessThanOrEqual": "6.3.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.4", "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": "5.15.121"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.1.36"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.3.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.4"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/eb947403518ea3d93f6d89264bb1f5416bb0c7d0"}, {"url": "https://git.kernel.org/stable/c/854156d12caa9d36de1cf5f084591c7686cc8a9d"}, {"url": "https://git.kernel.org/stable/c/d1066c1b3663401cd23c0d6e60cdae750ce00c0f"}, {"url": "https://git.kernel.org/stable/c/5005bcb4219156f1bf7587b185080ec1da08518e"}], "title": "ksmbd: validate session id and tree id in the compound request", "x_generator": {"engine": "bippy-1.2.0"}}}}

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So work->sess and work->tcon could be NULL.\nIf secound request in the compound access work->sess or tcon, It cause\nNULL pointer dereferecing error."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ksmbd: valida el ID de sesi\u00f3n y el ID de \u00e1rbol en la solicitud compuesta. Este parche valida el ID de sesi\u00f3n y el ID de \u00e1rbol en la solicitud compuesta. Si la primera operaci\u00f3n en la solicitud compuesta es una solicitud ECHO SMB2, ksmbd omite la validaci\u00f3n de sesi\u00f3n y \u00e1rbol. Por lo tanto, work->sess y work->tcon podr\u00edan ser NULL. Si la segunda solicitud en la solicitud compuesta accede a work->sess o tcon, se produce un error de desreferenciaci\u00f3n de puntero NULL."}], "id": "CVE-2023-3866", "lastModified": "2026-08-04T10:18:25.907", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2025-08-16T14:15:27.383", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5005bcb4219156f1bf7587b185080ec1da08518e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/854156d12caa9d36de1cf5f084591c7686cc8a9d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/d1066c1b3663401cd23c0d6e60cdae750ce00c0f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/eb947403518ea3d93f6d89264bb1f5416bb0c7d0"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-476"}], "source": "nvd@nist.gov", "type": "Primary"}]}

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{"created": "2025-08-18T20:49:59.560649+00:00", "updated": "2025-08-18T20:49:59.560729+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}