{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-98281",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-98281"
  ],
  "published": "2026-10-06T08:47:10Z",
  "summary": "futex: Also allocate private hash on vfork()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Also allocate private hash on vfork()\n\nAs Jann demonstrated, it is entirely feasible to access the mm through vfork().\nTherefore we need to allocate a private hash on vfork() as well as any other\nCLONE_VM user.\n\nSpecifically, it must be avoided to have (private) futex waiters before\nallocating the private hash.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:13",
        "name": "linux"
      },
      "versions": [
        "1:6.18.33-1+rpt1",
        "1:6.18.34-1+rpt1",
        "1:6.18.39-1+rpt1",
        "1:6.18.50-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-2712",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v6",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v7",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v8",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.33+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.33-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-2712",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v6",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v7",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v8",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.34+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-2712",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v6",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v7",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v8",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.39+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.39-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-2712",
            "binary_version": "1:6.18.50-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-v6",
            "binary_version": "1:6.18.50-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-v7",
            "binary_version": "1:6.18.50-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-v8",
            "binary_version": "1:6.18.50-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.18.50+rpt-rpi-v8-rt",
            "binary_version": "1:6.18.50-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.18.33-1+rpt1": {
            "linux_commit": "95b85bebbedcaedfa7ca79116ed38b7376fba412",
            "upstream_version": "6.18.33",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.54"
          },
          "1:6.18.34-1+rpt1": {
            "linux_commit": "c8c7494100e99ee05b11aaa4f0588a223a63d1af",
            "upstream_version": "6.18.34",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.54"
          },
          "1:6.18.39-1+rpt1": {
            "linux_commit": "60ea684a8ace97bb0db1a16e20753bdd6ab371ff",
            "upstream_version": "6.18.39",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.54"
          },
          "1:6.18.50-1+rpt1": {
            "linux_commit": "cff533aec2fa601846766b32ff57204e0a61bed7",
            "upstream_version": "6.18.50",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.54"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-98281"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5468a4855b63b30156a79e5248e01bf1a2c18dd7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/eecbafa8cabbc4d1482f6a5e2acc25a8f934681b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b61b6f95d6722ddbbbd09e689fa41b55fd36f9a5"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-10-07T06:50:27Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The trigger is a local process calling vfork()/clone3(CLONE_VM|CLONE_VFORK) in kernel_clone()/copy_process(), where need_futex_hash_allocate_default() skipped the private hash, followed by futex() syscalls on the shared mm. No remote peer supplies any input.\nAC:L - The attacker owns every task involved: the vfork parent (killed through its TASK_KILLABLE wait_for_vfork_done, so its futex exit path runs on the shared mm) and the vfork child, which creates a thread to publish the first private hash. Both sides of the race are under attacker control, so it can be retried at will.\nPR:L - vfork, clone, futex(FUTEX_WAIT/LOCK_PI), robust lists and kill() all work for an ordinary unprivileged user with no capability checks. The hash allocation in futex_hash_allocate_default() has no privilege gate either.\nUI:N - The attacker's own processes create the shared-mm state and the futex operations. No other user has to do anything.\nS:U - The damaged objects are kernel futex state (mm->futex.phash, hash buckets, pi_state) inside the same kernel security authority. No guest/host or IOMMU boundary is crossed.\nC:H - __futex_pivot_hash() leaves waiters queued in the global hash when the private hash is first published, so later PI/requeue operations take a different bucket lock. Futex PI state handled under two different bucket locks is the classic futex use-after-free pattern, and the earlier bug from this same assumption was a KASAN use-after-free, so kernel memory disclosure is plausible.\nI:H - A freed pi_state or private-hash reference that the attacker can reallocate gives a kernel heap write primitive, as in earlier futex PI use-after-free exploits, so local privilege escalation is possible.\nA:H - Waiters stranded in the global hash miss every later wake that goes to the private bucket, which hangs the affected tasks. The pi_state/reference corruption from inconsistent bucket locking can cause a KASAN splat or kernel oops."
    }
  }
}