{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98942", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.381Z", "datePublished": "2026-10-23T12:12:14.180Z", "dateUpdated": "2026-10-26T06:56:52.637Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-26T06:56:52.637Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Build the cid tables privately and publish them with RCU\n\nThe cid tables are visible to the cid kfuncs while being modified: the\nfirst enable publishes the global pointers before filling them,\nops.init_cids() overrides rewrite them in place, and re-enables rebuild\nthem in place. A racing TRACING or SYSCALL program can read unfilled\nentries, including uninitialized memory in the kmalloc'd tables, or torn\ntopo updates.\n\nTie the tables' lifetimes to the root sched instead: each root enable\nbuilds a fresh set privately and publishes the per-table __rcu globals once\nthe layout is final, and root disable unpublishes and RCU-frees the set. A\nnon-NULL global is now always a fully built table which stays valid for the\nreader's RCU read section, and lookups stay two loads. Kfuncs treat NULL as\nno-mapping, also after the scheduler exits instead of reporting the stale\nlast mapping.\n\nThe cid kfuncs are available whether the root scheduler is cid-form or\ncpu-form, the latter to allow gradual migration to cids. Every root\ntherefore builds and publishes a default mapping.\n\nEvery reader must either be gated on scheduler liveness or NULL-check\ninside an RCU read section. Fix the two kfuncs that were neither:\nscx_bpf_this_cid() read the table with no RCU or preemption protection and\nscx_bpf_task_cid() relied on KF_RCU, which doesn't put a sleepable program\nin an RCU read section. The hotplug callbacks are instead serialized by\nretiring the tables inside the cpus_read_lock() section that clears\nscx_root.\n\nv2: Document why every root builds the tables (desc + cid.c comment)."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/sched/ext/cid.c", "kernel/sched/ext/cid.h", "kernel/sched/ext/ext.c", "kernel/sched/ext/internal.h", "kernel/sched/ext/sub.c"], "versions": [{"version": "e9b55af47edf6e60c9a47b5604c3e15c5162ec86", "lessThan": "0e1a74369bdbc357d3d9713734418d914a981553", "status": "affected", "versionType": "git"}, {"version": "e9b55af47edf6e60c9a47b5604c3e15c5162ec86", "lessThan": "3a773220d39ba993dfe5d135f8b610be10794d5d", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/sched/ext/cid.c", "kernel/sched/ext/cid.h", "kernel/sched/ext/ext.c", "kernel/sched/ext/internal.h", "kernel/sched/ext/sub.c"], "versions": [{"version": "7.2", "status": "affected"}, {"version": "0", "lessThan": "7.2", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.10", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "7.2", "versionEndExcluding": "7.2.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/0e1a74369bdbc357d3d9713734418d914a981553"}, {"url": "https://git.kernel.org/stable/c/3a773220d39ba993dfe5d135f8b610be10794d5d"}], "title": "sched_ext: Build the cid tables privately and publish them with RCU", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["kernel/sched/ext/cid.c", "kernel/sched/ext/cid.h", "kernel/sched/ext/ext.c", "kernel/sched/ext/internal.h", "kernel/sched/ext/sub.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "0e1a74369bdbc357d3d9713734418d914a981553", "status": "affected", "version": "e9b55af47edf6e60c9a47b5604c3e15c5162ec86", "versionType": "git"}, {"lessThan": "3a773220d39ba993dfe5d135f8b610be10794d5d", "status": "affected", "version": "e9b55af47edf6e60c9a47b5604c3e15c5162ec86", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["kernel/sched/ext/cid.c", "kernel/sched/ext/cid.h", "kernel/sched/ext/ext.c", "kernel/sched/ext/internal.h", "kernel/sched/ext/sub.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "7.2"}, {"lessThan": "7.2", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.10", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Build the cid tables privately and publish them with RCU\n\nThe cid tables are visible to the cid kfuncs while being modified: the\nfirst enable publishes the global pointers before filling them,\nops.init_cids() overrides rewrite them in place, and re-enables rebuild\nthem in place. A racing TRACING or SYSCALL program can read unfilled\nentries, including uninitialized memory in the kmalloc'd tables, or torn\ntopo updates.\n\nTie the tables' lifetimes to the root sched instead: each root enable\nbuilds a fresh set privately and publishes the per-table __rcu globals once\nthe layout is final, and root disable unpublishes and RCU-frees the set. A\nnon-NULL global is now always a fully built table which stays valid for the\nreader's RCU read section, and lookups stay two loads. Kfuncs treat NULL as\nno-mapping, also after the scheduler exits instead of reporting the stale\nlast mapping.\n\nThe cid kfuncs are available whether the root scheduler is cid-form or\ncpu-form, the latter to allow gradual migration to cids. Every root\ntherefore builds and publishes a default mapping.\n\nEvery reader must either be gated on scheduler liveness or NULL-check\ninside an RCU read section. Fix the two kfuncs that were neither:\nscx_bpf_this_cid() read the table with no RCU or preemption protection and\nscx_bpf_task_cid() relied on KF_RCU, which doesn't put a sleepable program\nin an RCU read section. The hotplug callbacks are instead serialized by\nretiring the tables inside the cpus_read_lock() section that clears\nscx_root.\n\nv2: Document why every root builds the tables (desc + cid.c comment)."}], "id": "CVE-2026-98942", "lastModified": "2026-10-26T07:17:18.007", "metrics": {}, "published": "2026-10-23T13:17:15.193", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0e1a74369bdbc357d3d9713734418d914a981553"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3a773220d39ba993dfe5d135f8b610be10794d5d"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}