CVE-2026-31717

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The flaw allows any authenticated SMB user to hijack another user's orphaned durable handle.\nUI:N - No victim interaction is required at exploit time; the attacker sends network SMB requests directly to the server.\nS:U - The impact remains within the ksmbd/file-server security authority and does not cross a VM, sandbox, or hardware isolation boundary.\nC:H - A hijacked durable handle can be used to read victim-opened files using the original handle's access rights, bypassing normal open-time ACL checks. This can expose full contents of sensitive files.\nI:H - The reconnected handle reuses the original `fp->daccess`, so if the victim handle had write, set-info, rename, truncate, or delete rights, the attacker can modify victim data with those rights.\nA:H - The attacker can steal or close the durable handle and, when the original handle carries write/delete/truncate rights, render victim data or critical shared files unavailable."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/mgmt/user_session.c", "fs/smb/server/oplock.c", "fs/smb/server/oplock.h", "fs/smb/server/smb2pdu.c", "fs/smb/server/vfs_cache.c", "fs/smb/server/vfs_cache.h"], "versions": [{"version": "8df4bcdb0a4232192b2445256c39b787d58ef14d", "lessThan": "712cdf917e77a6444ce3836874829d770db20ee6", "status": "affected", "versionType": "git"}, {"version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d", "status": "affected", "versionType": "git"}, {"version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "00ce8d6789dae72d042a4522264964c72891ca37", "status": "affected", "versionType": "git"}, {"version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "c908c853f304a4969b5aa10eba0b50350cc65b80", "status": "affected", "versionType": "git"}, {"version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a", "status": "affected", "versionType": "git"}, {"version": "6.6.32", "lessThan": "6.6.142", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/mgmt/user_session.c", "fs/smb/server/oplock.c", "fs/smb/server/oplock.h", "fs/smb/server/smb2pdu.c", "fs/smb/server/vfs_cache.c", "fs/smb/server/vfs_cache.h"], "versions": [{"version": "6.9", "status": "affected"}, {"version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.142", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.25", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.2", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "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": "6.6.32", "versionEndExcluding": "6.6.142"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.12.92"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.25"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.0.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/712cdf917e77a6444ce3836874829d770db20ee6"}, {"url": "https://git.kernel.org/stable/c/c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d"}, {"url": "https://git.kernel.org/stable/c/00ce8d6789dae72d042a4522264964c72891ca37"}, {"url": "https://git.kernel.org/stable/c/c908c853f304a4969b5aa10eba0b50350cc65b80"}, {"url": "https://git.kernel.org/stable/c/49110a8ce654bbe56bef7c5e44cce31f4b102b8a"}], "title": "ksmbd: validate owner of durable handle on reconnect", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

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Esto permite a cualquier usuario autenticado secuestrar un identificador duradero hu\u00e9rfano prediciendo o forzando por fuerza bruta el ID persistente.\n\nSeg\u00fan MS-SMB2, el servidor DEBE verificar que el SecurityContext de la solicitud de reconexi\u00f3n coincide con el SecurityContext asociado con la apertura existente.\nA\u00f1adir una estructura durable_owner a ksmbd_file para almacenar el UID, GID y nombre de cuenta del abridor original. Y capturar la informaci\u00f3n del propietario cuando un identificador de archivo queda hu\u00e9rfano. E implementar ksmbd_vfs_compare_durable_owner() para validar la identidad del solicitante durante SMB2_CREATE (DHnC)."}], "id": "CVE-2026-31717", "lastModified": "2026-11-11T21:10:00.200", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-05-01T14:16:21.860", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/00ce8d6789dae72d042a4522264964c72891ca37"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/49110a8ce654bbe56bef7c5e44cce31f4b102b8a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/712cdf917e77a6444ce3836874829d770db20ee6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/c908c853f304a4969b5aa10eba0b50350cc65b80"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: ksmbd: validate owner of durable handle on reconnect", "id": "2464401", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2464401"}, "csaw": false, "cwe": "CWE-708", "details": ["A flaw was found in ksmbd, a component of the Linux kernel. This vulnerability allows an authenticated user to hijack an orphaned durable handle by predicting or brute-forcing its persistent ID. This could lead to unauthorized access to file sessions and potentially sensitive data or services."], "name": "CVE-2026-31717", "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": "2026-05-01T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-31717\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31717\nhttps://lore.kernel.org/linux-cve-announce/2026050124-CVE-2026-31717-f68b@gregkh/T"]}

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