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-2026-72382",
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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": "2026-08-09T03:40:39.923Z",
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"datePublished": "2026-08-15T05:56:14.103Z",
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"dateUpdated": "2026-10-30T12:29:13.532Z"
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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": "2026-10-30T12:29:13.532Z"
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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: reject undersized DACLs before parsing ACEs\n\nparse_dacl() limits the attacker-controlled ACE count by comparing it\nwith the number of minimal ACEs that fit in the DACL size. The DACL size\nfield is 16 bits, but the expression subtracts sizeof(struct smb_acl).\nBecause sizeof() is unsigned, a DACL size smaller than the ACL header\nunderflows to a large size_t.\n\nA malicious client can reach this with:\n\nSMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY)\n -> smb2_set_info_sec()\n -> set_info_sec()\n -> parse_sec_desc()\n -> parse_dacl()\n -> init_acl_state(..., 0xffff)\n -> init_acl_state(..., 0xffff)\n -> kmalloc_objs(..., 0xffff)\n\nThus a malformed security descriptor can make num_aces pass the guard\nand drive large temporary ACL state and pointer-array allocations.\n\nReject DACLs smaller than struct smb_acl before doing the subtraction,\nso the ACE count check cannot be bypassed by the underflow."
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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 flaw is reached through ksmbd's in-kernel SMB2 server on TCP/445 via SMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY) or SMB2 CREATE with an SD buffer, both handled from remote network input.\nAC:L - An attacker reliably triggers the bug by sending a crafted security descriptor with DACL size below 8 bytes and a large num_aces (e.g. 0xFFFF), bypassing the underflowed ACE-count check without special timing or victim state.\nPR:L - Exploitation requires an authenticated SMB session, a writable tree connect, an open file handle (or CREATE with SD buffer), and FILE_WRITE_DAC or FILE_WRITE_OWNER access on that object.\nUI:N - No victim interaction is required beyond the attacker sending malicious SMB2 protocol requests to an exposed ksmbd server.\nS:U - Impact is confined to kernel memory exhaustion and ksmbd availability within the same host security authority; it does not cross VM, container, or IOMMU boundaries.\nC:H - The unsigned underflow bypasses DACL bounds validation, letting attacker-controlled num_aces drive multi-megabyte kernel heap allocations and parse attacker-supplied ACE data from malformed security descriptors.\nI:H - Attacker-controlled allocation sizing from bypassed validation creates large heap manipulation primitives in kernel context, consistent with similar ksmbd DACL integer-validation flaws scored at high integrity impact.\nA:H - Each malicious request forces roughly 2.5 MB of kernel allocations; repeated or concurrent SMB2_SET_INFO calls can exhaust memory, trigger OOM/page-allocator failures, and deny service to ksmbd and the host."
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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/smbacl.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": "8dc949061e35427433feac3ebe5ec089f2aa857e",
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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": "16fb65ec15fe7c90f50a2115854bfd9a032d4023",
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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": "282847c0cf22f2e961155ac8e42f6eeab7e16049",
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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": "d020e7f27bf65eecd3805404702f716b2b6d9e73",
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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": "15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd",
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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": "60908f7ebcd9b6cde74ad5711fab0f49c7970949",
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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/smbacl.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": "6.1.191",
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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": "6.12.97",
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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": "6.18.40",
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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": "7.1.5",
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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": "6.1.191"
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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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"versionStartIncluding": "5.15",
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"versionEndExcluding": "6.12.97"
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{
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"versionStartIncluding": "5.15",
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.15",
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"versionEndExcluding": "7.1.5"
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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/8dc949061e35427433feac3ebe5ec089f2aa857e"
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},
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{
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"url": "https://git.kernel.org/stable/c/16fb65ec15fe7c90f50a2115854bfd9a032d4023"
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},
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{
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"url": "https://git.kernel.org/stable/c/282847c0cf22f2e961155ac8e42f6eeab7e16049"
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},
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{
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"url": "https://git.kernel.org/stable/c/d020e7f27bf65eecd3805404702f716b2b6d9e73"
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},
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{
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"url": "https://git.kernel.org/stable/c/15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd"
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},
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{
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"url": "https://git.kernel.org/stable/c/60908f7ebcd9b6cde74ad5711fab0f49c7970949"
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}
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],
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"title": "ksmbd: reject undersized DACLs before parsing ACEs",
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"x_generator": {
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} |