222 lines
12 KiB
JSON
222 lines
12 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-64394",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-07-19T15:36:31.785Z",
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"datePublished": "2026-07-25T08:50:39.797Z",
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"dateUpdated": "2026-08-17T04:54:47.889Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-08-17T04:54:47.889Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: add a WRITE_DAC/WRITE_OWNER check to SMB2 SET_INFO SECURITY\n\ncommit cc57232cae23 (\"ksmbd: fix FSCTL permission bypass by adding a\npermission check for FSCTL_SET_SPARSE\") added a fp->daccess gate to\nfsctl_set_sparse and noted that \"similar handle-level checks exist in other\nfunctions but are missing here.\" The SMB2 SET_INFO SECURITY arm is one of\nthe missing ones, and the most security-relevant: smb2_set_info_sec() calls\nset_info_sec() with no per-handle access check.\n\nset_info_sec() (fs/smb/server/smbacl.c) re-permissions the file: it\nrewrites owner/group/mode via notify_change(), rewrites the POSIX ACL via\nset_posix_acl(), and on KSMBD_SHARE_FLAG_ACL_XATTR shares removes and\nrewrites the Windows security descriptor via ksmbd_vfs_set_sd_xattr().\nEvery other persistent-mutation arm of the sibling handler\nsmb2_set_info_file() checks fp->daccess first (FILE_WRITE_DATA /\nFILE_DELETE / FILE_WRITE_EA / FILE_WRITE_ATTRIBUTES); the SECURITY arm —\nwhich mutates the access control itself — is the only one with no gate.\n\nA client can therefore open a handle with FILE_WRITE_ATTRIBUTES only (no\nFILE_WRITE_DAC / FILE_WRITE_OWNER) and use SMB2_SET_INFO with InfoType\nSMB2_O_INFO_SECURITY to rewrite the file's DACL and owner, granting itself\naccess the handle's daccess never carried. Unlike the FSCTL data arms this\nis a metadata/xattr operation, so there is no FMODE_WRITE VFS backstop —\nthe missing fp->daccess check is the entire gate.\n\nSetting a security descriptor is the WRITE_DAC / WRITE_OWNER operation, so\nrequire at least one of those on the handle before re-permissioning the\nfile. -EACCES is mapped to STATUS_ACCESS_DENIED by smb2_set_info()."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 8.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:N - The vulnerable SMB2 SET_INFO handler is remotely reachable through ksmbd over TCP port 445.\nAC:L - An attacker can deterministically open an attribute-only handle and submit a crafted security descriptor, with no race or uncontrollable condition.\nPR:L - A valid SMB session, writable tree connection, and permission to open the target with FILE_WRITE_ATTRIBUTES are required, but no administrative privileges are needed.\nUI:N - The attacker directly sends the SMB requests without requiring any victim action.\nS:U - The bypass affects files governed by the same host and ksmbd share security authority and does not cross a virtualization or sandbox boundary.\nC:H - The attacker can rewrite the DACL and mode to grant read access, potentially disclosing complete protected files within the share.\nI:H - The attacker can grant itself write or delete rights and subsequently modify or destroy protected file contents, ownership metadata, and ACLs.\nA:H - The attacker can deny legitimate access or grant itself sufficient rights to corrupt or destroy affected share data, causing complete loss of availability for those resources."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"fs/smb/server/smb2pdu.c"
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],
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"versions": [
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{
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"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
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"lessThan": "0848b1d8b403f530878195dcbe241a2fddb9d0e1",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
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"lessThan": "e6aa731f1b4b3e08caebf66a99f04b22bdab2e99",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
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"lessThan": "9ab2ffd3ed3d4ca1667c52de27026ddabc11e537",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
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"lessThan": "f56535db508ead8dec1c481ad93d7d8acd8f8f1e",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
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"lessThan": "aae600cdaffc6d9ce97645f129799a103a97d06d",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
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"lessThan": "44df157a1183a7f746caa970c169255da5ac61f8",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"fs/smb/server/smb2pdu.c"
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],
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"versions": [
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{
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"version": "5.15",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "5.15",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.1.178",
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"lessThanOrEqual": "6.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.6.145",
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"lessThanOrEqual": "6.6.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12.96",
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"lessThanOrEqual": "6.12.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.39",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.1.4",
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"lessThanOrEqual": "7.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
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"versionEndExcluding": "6.1.178"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
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"versionEndExcluding": "6.6.145"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
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"versionEndExcluding": "6.12.96"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
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"versionEndExcluding": "6.18.39"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
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"versionEndExcluding": "7.1.4"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
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"versionEndExcluding": "7.2"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/0848b1d8b403f530878195dcbe241a2fddb9d0e1"
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},
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{
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"url": "https://git.kernel.org/stable/c/e6aa731f1b4b3e08caebf66a99f04b22bdab2e99"
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},
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{
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"url": "https://git.kernel.org/stable/c/9ab2ffd3ed3d4ca1667c52de27026ddabc11e537"
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},
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{
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"url": "https://git.kernel.org/stable/c/f56535db508ead8dec1c481ad93d7d8acd8f8f1e"
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},
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{
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"url": "https://git.kernel.org/stable/c/aae600cdaffc6d9ce97645f129799a103a97d06d"
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},
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{
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"url": "https://git.kernel.org/stable/c/44df157a1183a7f746caa970c169255da5ac61f8"
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}
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],
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"title": "ksmbd: add a WRITE_DAC/WRITE_OWNER check to SMB2 SET_INFO SECURITY",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |