{
  "cveId": "CVE-2026-98942",
  "url": "https://patchblox.com/security/cve/CVE-2026-98942",
  "summary": "CVE-2026-98942 is fixed in linux on 1 platform by DEBIAN-CVE-2026-98942 (version 7.2.10-1), released October 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "sched_ext: Build the cid tables privately and publish them with RCU",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  sched_ext: Build the cid tables privately and publish them with RCU  The cid tables are visible to the cid kfuncs while being modified: the first enable publishes the global pointers before filling them, ops.init_cids() overrides rewrite them in place, and re-enables rebuild them in place. A racing TRACING or SYSCALL program can read unfilled entries, including uninitialized memory in the kmalloc\u0027d tables, or torn topo updates.  Tie the tables\u0027 lifetimes to the root sched instead: each root enable builds a fresh set privately and publishes the per-table __rcu globals once the layout is final, and root disable unpublishes and RCU-frees the set. A non-NULL global is now always a fully built table which stays valid for the reader\u0027s RCU read section, and lookups stay two loads. Kfuncs treat NULL as no-mapping, also after the scheduler exits instead of reporting the stale last mapping.  The cid kfuncs are available whether the root scheduler is cid-form or cpu-form, the latter to allow gradual migration to cids. Every root therefore builds and publishes a default mapping.  Every reader must either be gated on scheduler liveness or NULL-check inside an RCU read section. Fix the two kfuncs that were neither: scx_bpf_this_cid() read the table with no RCU or preemption protection and scx_bpf_task_cid() relied on KF_RCU, which doesn\u0027t put a sleepable program in an RCU read section. The hotplug callbacks are instead serialized by retiring the tables inside the cpus_read_lock() section that clears scx_root.  v2: Document why every root builds the tables (desc \u002B cid.c comment).",
  "published": "2026-10-23T13:17:15Z",
  "severity": "Moderate",
  "cvss": 4.7,
  "epss": 0.00163,
  "epssPercentile": 0.05526,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98942",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.10-1",
      "fix": "DEBIAN-CVE-2026-98942",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98942",
      "released": "2026-10-24T13:25:57Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}