CVE-2026-80758 (GCVE-0-2026-80758)
Vulnerability from cvelistv5
Published
2026-09-04 15:12
Modified
2026-10-19 08:43
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: futex: Avoid private hash use-after-free on final put futex_private_hash_put() drops the reference to fph before evaluating fph->mm for wake_up_var(). futex_ref_put() enables preemption again before returning. If that put drops the final reference and the task is preempted, another task can pivot to the replacement hash and free the old hash after an RCU grace period. The first task then reads fph->mm from the freed allocation when it resumes. KASAN reports a slab-use-after-free in futex_private_hash_put(), with the read at offset 24 in a freed kmalloc-512 allocation. The allocation and free stacks point to futex_hash_allocate() and the RCU free path, respectively. Load the mm pointer while the fph reference is still held and pass the saved value to wake_up_var(). wake_up_var() uses the pointer as a waitqueue key and does not dereference the mm through it.
References
Impacted products
Vendor Product Version
Linux Linux Version: bd54df5ea7cadac520e346d5f0fe5d58e635b6ba
Version: bd54df5ea7cadac520e346d5f0fe5d58e635b6ba
Version: bd54df5ea7cadac520e346d5f0fe5d58e635b6ba
Version: bd54df5ea7cadac520e346d5f0fe5d58e635b6ba
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/futex/core.c"
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          "vendor": "Linux",
          "versions": [
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              "version": "0",
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              "versionType": "semver"
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              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Avoid private hash use-after-free on final put\n\nfutex_private_hash_put() drops the reference to fph before evaluating\nfph-\u003emm for wake_up_var(). futex_ref_put() enables preemption again before\nreturning. If that put drops the final reference and the task is preempted,\nanother task can pivot to the replacement hash and free the old hash after\nan RCU grace period. The first task then reads fph-\u003emm from the freed\nallocation when it resumes.\n\nKASAN reports a slab-use-after-free in futex_private_hash_put(), with the\nread at offset 24 in a freed kmalloc-512 allocation. The allocation and\nfree stacks point to futex_hash_allocate() and the RCU free path,\nrespectively.\n\nLoad the mm pointer while the fph reference is still held and pass the\nsaved value to wake_up_var(). wake_up_var() uses the pointer as a waitqueue\nkey and does not dereference the mm through it."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:43:14.380Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/dba60d26e9dda3e157ad6b0934d4232f6c6904ee"
        },
        {
          "url": "https://git.kernel.org/stable/c/12cd315a7b6a7d7db3f69d98bfe3909275e9451d"
        },
        {
          "url": "https://git.kernel.org/stable/c/25408c62ed4ebcd491d0e9e4b4a5b512547512e4"
        },
        {
          "url": "https://git.kernel.org/stable/c/1c7efabfbaf796f11000a46094a69955a01ec6cc"
        }
      ],
      "title": "futex: Avoid private hash use-after-free on final put",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80758",
    "datePublished": "2026-09-04T15:12:27.689Z",
    "dateReserved": "2026-08-26T14:34:25.791Z",
    "dateUpdated": "2026-10-19T08:43:14.380Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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