{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93229","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-17T16:02:15.094Z","datePublished":"2026-09-24T15:29:14.322Z","dateUpdated":"2026-09-25T05:09:49.321Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-25T05:09:49.321Z"},"descriptions":[{"lang":"en","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() ]"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfsctl.c"],"versions":[{"version":"bd9d6a3efa9709e653aafbeb859289feccb8e70c","lessThan":"f501f2f4ec1d2dfe39e21c98630314074a9b30b0","status":"affected","versionType":"git"},{"version":"bd9d6a3efa9709e653aafbeb859289feccb8e70c","lessThan":"1aea0482b98ecd7d0249204665f2ad4ad517f66b","status":"affected","versionType":"git"},{"version":"bd9d6a3efa9709e653aafbeb859289feccb8e70c","lessThan":"9b5f6475006cd8e3b5b99b8eb3cd74dbb1ce9df8","status":"affected","versionType":"git"},{"version":"bd9d6a3efa9709e653aafbeb859289feccb8e70c","lessThan":"a71f161a857117e8e0264deb7d14fff5c98adcf5","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfsctl.c"],"versions":[{"version":"6.7","status":"affected"},{"version":"0","lessThan":"6.7","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","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":"6.7","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f501f2f4ec1d2dfe39e21c98630314074a9b30b0"},{"url":"https://git.kernel.org/stable/c/1aea0482b98ecd7d0249204665f2ad4ad517f66b"},{"url":"https://git.kernel.org/stable/c/9b5f6475006cd8e3b5b99b8eb3cd74dbb1ce9df8"},{"url":"https://git.kernel.org/stable/c/a71f161a857117e8e0264deb7d14fff5c98adcf5"}],"title":"nfsd: add missing read barrier to rpc_status_get dumpit seqcount retry","x_generator":{"engine":"bippy-1.2.0"}}}}