180 lines
11 KiB
JSON
180 lines
11 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-2026-93229",
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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": "2026-09-17T16:02:15.094Z",
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"datePublished": "2026-09-24T15:29:14.322Z",
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"dateUpdated": "2026-10-19T09:07:41.099Z"
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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": "2026-10-19T09:07:41.099Z"
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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\nnfsd: add missing read barrier to rpc_status_get dumpit seqcount retry\n\nThe hand-rolled seqcount-like protocol in nfsd_nl_rpc_status_get_dumpit()\nis missing a read memory barrier (smp_rmb) before its second counter\ncheck. The standard kernel read_seqcount_retry() includes smp_rmb()\nto ensure that all data reads complete before the counter is re-checked.\n\nWithout this barrier, on weakly-ordered architectures (ARM, POWER),\nthe CPU may reorder field reads past the second counter check, making\nthe retry logic ineffective: it could observe a consistent counter pair\nwhile reading fields that have been concurrently modified by the writer.\n\nAdd smp_rmb() before the second counter check to order the field reads\nahead of it, matching the barrier semantics of the standard seqcount\nread-side. The begin-side smp_load_acquire() already pairs with the\nsmp_store_release() in nfsd_dispatch(); with the smp_rmb() now ordering\nthe field reads, the retry check no longer needs acquire semantics and\nreads the counter with a plain READ_ONCE(), as read_seqcount_retry()\ndoes.\n\n[ cel: Use READ_ONCE instead of smp_load_acquire() ]"
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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:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
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"baseScore": 7.1,
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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:L - The missing smp_rmb is in nfsd_nl_rpc_status_get_dumpit(), reached only via NFSD_CMD_RPC_STATUS_GET over AF_NETLINK (nfsd_nl_ops dumpit). Remote NFS RPCs in nfsd_dispatch() only write rq_status_counter and never enter dumpit, so exploitation requires local netlink.\nAC:L - The attacker loops NFSD_CMD_RPC_STATUS_GET while sending NFSv4 COMPOUNDs with more than eight ops so nfsd_dispatch() smp_store_release()s rq_status_counter and nfsd4_release_compoundargs() mutates args->ops/opcnt. Both sides of the seqcount race are attacker-driven; weakly-ordered ARM/POWER where the missing smp_rmb matters is mainstream.\nPR:L - NFSD_CMD_RPC_STATUS_GET is registered in nfsd_nl_ops with GENL_CMD_CAP_DUMP and no GENL_ADMIN_PERM, so genl_family_rcv_msg() skips the CAP_NET_ADMIN check. Any unprivileged process in the nfsd network namespace can invoke the dump.\nUI:N - The attacker issues the NFSD_CMD_RPC_STATUS_GET dump and the concurrent NFSv4 COMPOUNDs themselves. No separate victim action such as mounting a filesystem or opening a device is required.\nS:U - The torn and out-of-bounds reads occur in host-kernel nfsd_nl_rpc_status_get_dumpit() on the local machine. Impact stays inside one security authority and is not a VM escape, IOMMU bypass, or other cross-boundary breakout.\nC:H - Without smp_rmb(), dumpit can pass the rq_status_counter retry and still load args->opcnt before nfsd4_release_compoundargs() zeros it and args->ops after it is switched to iops[8]. Indices 8-15 then read adjacent slab at nfsd4_op stride and return those u32s via NFSD_A_RPC_STATUS_COMPOUND_OPS.\nI:N - nfsd_nl_rpc_status_get_dumpit() only copies opnum, xid, addresses and related fields into a stack nfsd_genl_rqstp for netlink. The missing retry barrier yields an out-of-bounds or torn read, not an out-of-bounds write, use-after-free write, or control-flow hijack.\nA:H - Slots 8-15 are sampled at sizeof(struct nfsd4_op) stride past the trailing iops[8] array in kmalloc'd nfsd4_compoundargs into adjacent or unmapped slab pages, which can oops nfsd_nl_rpc_status_get_dumpit() even if the leak is not turned into a stable read."
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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/nfsd/nfsctl.c"
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],
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"versions": [
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{
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"version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c",
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"lessThan": "f501f2f4ec1d2dfe39e21c98630314074a9b30b0",
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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": "bd9d6a3efa9709e653aafbeb859289feccb8e70c",
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"lessThan": "1aea0482b98ecd7d0249204665f2ad4ad517f66b",
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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": "bd9d6a3efa9709e653aafbeb859289feccb8e70c",
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"lessThan": "9b5f6475006cd8e3b5b99b8eb3cd74dbb1ce9df8",
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"status": "affected",
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{
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"lessThan": "a71f161a857117e8e0264deb7d14fff5c98adcf5",
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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/nfsd/nfsctl.c"
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],
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"versions": [
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{
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"version": "6.7",
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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": "6.7",
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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": "6.12.109",
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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": "6.18.50",
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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": "7.2.4",
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"lessThanOrEqual": "7.2.*",
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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": "7.3",
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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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"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": "6.7",
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"versionEndExcluding": "6.12.109"
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},
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"versionEndExcluding": "7.2.4"
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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/f501f2f4ec1d2dfe39e21c98630314074a9b30b0"
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},
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{
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"url": "https://git.kernel.org/stable/c/1aea0482b98ecd7d0249204665f2ad4ad517f66b"
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},
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{
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"url": "https://git.kernel.org/stable/c/9b5f6475006cd8e3b5b99b8eb3cd74dbb1ce9df8"
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},
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{
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"url": "https://git.kernel.org/stable/c/a71f161a857117e8e0264deb7d14fff5c98adcf5"
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}
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],
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"title": "nfsd: add missing read barrier to rpc_status_get dumpit seqcount retry",
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"x_generator": {
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} |