GHSA-9QJ4-WR4G-7M6F

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-09-03 15:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

futex: Drop CLONE_THREAD requirement for private default hash alloc

Currently need_futex_hash_allocate_default() depends on strict pthread semantics, abusing CLONE_THREAD. This breaks the non-concurrency assumptions when doing the mm->futex_ref pcpu allocations, leading to bugs[0] when sharing the mm in other ways; ie:

BUG: KASAN: slab-use-after-free in futex_hash_put

... where the +1 bias can end up on a percpu counter that mm->futex_ref no longer points at.

Loosen the check to cover any CLONE_VM clone, except vfork(). Excluding vfork keeps the existing paths untouched (no overhead), and we can't race in the first place: either the parent is suspended and the child runs alone, or mm->futex_ref is already allocated from an earlier CLONE_VM.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-52973"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416",
      "CWE-825"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T17:17:07Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Drop CLONE_THREAD requirement for private default hash alloc\n\nCurrently need_futex_hash_allocate_default() depends on strict pthread\nsemantics, abusing CLONE_THREAD.  This breaks the non-concurrency\nassumptions when doing the mm-\u003efutex_ref pcpu allocations, leading to\nbugs[0] when sharing the mm in other ways; ie:\n\n    BUG: KASAN: slab-use-after-free in futex_hash_put\n\n... where the +1 bias can end up on a percpu counter that mm-\u003efutex_ref\nno longer points at.\n\nLoosen the check to cover any CLONE_VM clone, except vfork().  Excluding\nvfork keeps the existing paths untouched (no overhead), and we can\u0027t\nrace in the first place: either the parent is suspended and the child\nruns alone, or mm-\u003efutex_ref is already allocated from an earlier\nCLONE_VM.",
  "id": "GHSA-9qj4-wr4g-7m6f",
  "modified": "2026-09-03T15:31:59Z",
  "published": "2026-06-24T18:32:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52973"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:45114"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:47040"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:62640"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:62642"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-52973"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492413"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1dcd36420af2da5bd59306dba9caf78e3d248b1d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/974ac49a9a068b0591a59f65c63eb06579a13091"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee9dce44362b2d8132c32964656ab6dff7dfbc6a"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52973.json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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