172 lines
9.4 KiB
JSON
172 lines
9.4 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-2023-54076",
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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": "2025-12-24T12:21:05.093Z",
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"datePublished": "2025-12-24T12:23:18.330Z",
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"dateUpdated": "2026-08-05T09:16:59.986Z"
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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": "2026-08-05T09:16:59.986Z"
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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\nsmb: client: fix missed ses refcounting\n\nUse new cifs_smb_ses_inc_refcount() helper to get an active reference\nof @ses and @ses->dfs_root_ses (if set). This will prevent\n@ses->dfs_root_ses of being put in the next call to cifs_put_smb_ses()\nand thus potentially causing an use-after-free bug."
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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:N/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 9.8,
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"baseSeverity": "CRITICAL"
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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 in the in-kernel SMB/CIFS network filesystem client, and the unbalanced puts are driven by data from the remote peer — the server picks the SMB2.0/2.1 dialect that routes signing through the buggy `smb2_calc_signature()`, returns the DFS referrals (`DFSREF_REFERRAL_SERVER`) that populate `ses->dfs_root_ses`, and controls the delayed CREATE replies that reach `smb2_handle_cancelled_mid()`. A malicious, compromised, or MITM'd SMB/DFS server drives the refcount underflow purely over the network.\nAC:L - The imbalance is deterministic, not a race: every `smb2_find_smb_ses_unlocked()` acquisition drops one extra reference on `ses->dfs_root_ses` at release, so the attacker simply drives enough signed exchanges to force the count to zero. No memory-layout or timing condition outside the attacker's control is needed.\nPR:N - The attacker is the remote SMB/DFS server (or a network MITM) and holds no privileges or account on the victim client; referral responses and dialect negotiation happen without any credential on the target system.\nUI:N - The `smb2transport.c` half of the bug is a steady-state runtime path — on an already-mounted DFS share, signature calculation, cancelled-MID handling, echo keepalives and the DFS cache refresh worker accumulate the extra puts with no user action at attack time.\nS:U - The premature free and subsequent corruption are confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Use-after-free on a `cifs_ses` object whose slot can be reoccupied by attacker-groomed heap data yields a read primitive, and the freed session still holds authentication material (`auth_key.response`, signing keys) and kernel pointers used by subsequent code.\nI:H - After the free, `cifs_put_smb_ses()` reads `ses->server` from freed memory and performs an indirect call via `server->ops->logoff()`, giving a control-flow hijack primitive; heap spraying over the freed `cifs_ses` converts this into arbitrary write/code execution.\nA:H - The refcount underflow frees a session still referenced by child sessions, tcons, and the DFS cache worker, reliably producing an oops/panic (and a `WARN_ON(ses->ses_count < 0)`) that takes down the machine."
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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/client/dfs.c",
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"fs/smb/client/smb2transport.c"
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],
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"versions": [
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{
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"version": "8e3554150d6c80a84b3cb046615d1a0e943811dc",
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"lessThan": "eb382196e6f6e05cfafdab797840e5a96c6e7bf0",
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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": "8e3554150d6c80a84b3cb046615d1a0e943811dc",
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"lessThan": "bf99f6be2d20146942bce6f9e90a0ceef12cbc1e",
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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": "f30d226bcc9f0e2d97b4a6e94c43a28148fbeab6",
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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": "c082c3be0f96e759ff2e361d929832fda0b93851",
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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": "6.2.15",
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"lessThan": "6.3",
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"status": "affected",
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"versionType": "semver"
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},
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{
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"version": "6.3.2",
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"lessThan": "6.4",
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"status": "affected",
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"versionType": "semver"
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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/client/dfs.c",
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"fs/smb/client/smb2transport.c"
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],
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"versions": [
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{
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"version": "6.4",
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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": "6.4",
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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": "6.4.7",
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"lessThanOrEqual": "6.4.*",
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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": "6.5",
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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": "6.4",
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"versionEndExcluding": "6.4.7"
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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": "6.4",
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"versionEndExcluding": "6.5"
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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": "6.2.15"
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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": "6.3.2"
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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/eb382196e6f6e05cfafdab797840e5a96c6e7bf0"
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},
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{
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"url": "https://git.kernel.org/stable/c/bf99f6be2d20146942bce6f9e90a0ceef12cbc1e"
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}
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],
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"title": "smb: client: fix missed ses refcounting",
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} |