{
  "cveId": "CVE-2026-98789",
  "url": "https://patchblox.com/security/cve/CVE-2026-98789",
  "summary": "CVE-2026-98789 is fixed in linux on 1 platform by DEBIAN-CVE-2026-98789 (version 7.2.10-1), released October 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "bpf: Fix objects stuck in free_by_rcu_ttrace",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  bpf: Fix objects stuck in free_by_rcu_ttrace  do_call_rcu_ttrace() returns early when call_rcu_ttrace_in_progress is set and leaves the objects in free_by_rcu_ttrace. __free_rcu() frees waiting_for_gp_ttrace only and clears the flag. Hence the objects that free_bulk() or __free_by_rcu() added while RCU tasks trace GP was in flight stay in free_by_rcu_ttrace until free_bulk() or alloc_bulk() is called for the same bpf_mem_cache again, which may never happen. The number of such objects is not bounded.  Turn call_rcu_ttrace_in_progress into three states: 0 - idle 1 - __free_rcu() is queued 2 - __free_rcu() is queued and free_by_rcu_ttrace got more objects since  do_call_rcu_ttrace() sets 2. __free_rcu() does cmpxchg(1 -\u003E 0) and starts the next GP when it fails. It cannot clear the flag first and check free_by_rcu_ttrace later, since bpf_mem_alloc_destroy() frees bpf_mem_cache without waiting for RCU callbacks when the flag is zero.  Now __free_rcu() queues itself, so the one that didn\u0027t see \u0027draining\u0027 may do call_rcu_tasks_trace() after rcu_barrier_tasks_trace() in free_mem_alloc(). Queue it under rcu_read_lock() and do synchronize_rcu() before the barriers. Calling rcu_barrier_tasks_trace() twice works too, but creating and destroying hash maps in a loop on many cpus slows down to one free_mem_alloc() per GP and kworkers pile up.",
  "published": "2026-10-18T16:17:32Z",
  "severity": "Moderate",
  "cvss": 4.4,
  "epss": 0.00155,
  "epssPercentile": 0.04688,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98789",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.10-1",
      "fix": "DEBIAN-CVE-2026-98789",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98789",
      "released": "2026-10-19T16:27:52Z"
    }
  ],
  "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"
  }
}