CVE-2026-23415 (GCVE-0-2026-23415)

Vulnerability from cvelistv5 – Published: 2026-04-02 11:40 – Updated: 2026-04-13 06:06
VLAI?
Title
futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()
Summary
In the Linux kernel, the following vulnerability has been resolved: futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy() During futex_key_to_node_opt() execution, vma->vm_policy is read under speculative mmap lock and RCU. Concurrently, mbind() may call vma_replace_policy() which frees the old mempolicy immediately via kmem_cache_free(). This creates a race where __futex_key_to_node() dereferences a freed mempolicy pointer, causing a use-after-free read of mpol->mode. [ 151.412631] BUG: KASAN: slab-use-after-free in __futex_key_to_node (kernel/futex/core.c:349) [ 151.414046] Read of size 2 at addr ffff888001c49634 by task e/87 [ 151.415969] Call Trace: [ 151.416732] __asan_load2 (mm/kasan/generic.c:271) [ 151.416777] __futex_key_to_node (kernel/futex/core.c:349) [ 151.416822] get_futex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593) Fix by adding rcu to __mpol_put().
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c042c505210dc3453f378df432c10fff3d471bc5 , < 853f70c67d1b37e368fdcb3e328c4b8c04f53ac0 (git)
Affected: c042c505210dc3453f378df432c10fff3d471bc5 , < 7e196194ea27bd49adf3551e2aceb83498eb73fe (git)
Affected: c042c505210dc3453f378df432c10fff3d471bc5 , < 190a8c48ff623c3d67cb295b4536a660db2012aa (git)
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    Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/mempolicy.h",
            "kernel/futex/core.c",
            "mm/mempolicy.c"
          ],
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          "versions": [
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              "versionType": "git"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "6.16"
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.0",
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                  "vulnerable": true
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()\n\nDuring futex_key_to_node_opt() execution, vma-\u003evm_policy is read under\nspeculative mmap lock and RCU. Concurrently, mbind() may call\nvma_replace_policy() which frees the old mempolicy immediately via\nkmem_cache_free().\n\nThis creates a race where __futex_key_to_node() dereferences a freed\nmempolicy pointer, causing a use-after-free read of mpol-\u003emode.\n\n[  151.412631] BUG: KASAN: slab-use-after-free in __futex_key_to_node (kernel/futex/core.c:349)\n[  151.414046] Read of size 2 at addr ffff888001c49634 by task e/87\n\n[  151.415969] Call Trace:\n\n[  151.416732]  __asan_load2 (mm/kasan/generic.c:271)\n[  151.416777]  __futex_key_to_node (kernel/futex/core.c:349)\n[  151.416822]  get_futex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593)\n\nFix by adding rcu to __mpol_put()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T06:06:59.580Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/853f70c67d1b37e368fdcb3e328c4b8c04f53ac0"
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          "url": "https://git.kernel.org/stable/c/7e196194ea27bd49adf3551e2aceb83498eb73fe"
        },
        {
          "url": "https://git.kernel.org/stable/c/190a8c48ff623c3d67cb295b4536a660db2012aa"
        }
      ],
      "title": "futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23415",
    "datePublished": "2026-04-02T11:40:56.476Z",
    "dateReserved": "2026-01-13T15:37:46.014Z",
    "dateUpdated": "2026-04-13T06:06:59.580Z",
    "state": "PUBLISHED"
  },
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  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-23415",
      "date": "2026-04-18",
      "epss": "0.00022",
      "percentile": "0.05972"
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    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23415\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-02T12:16:20.810\",\"lastModified\":\"2026-04-03T16:10:52.680\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nfutex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()\\n\\nDuring futex_key_to_node_opt() execution, vma-\u003evm_policy is read under\\nspeculative mmap lock and RCU. Concurrently, mbind() may call\\nvma_replace_policy() which frees the old mempolicy immediately via\\nkmem_cache_free().\\n\\nThis creates a race where __futex_key_to_node() dereferences a freed\\nmempolicy pointer, causing a use-after-free read of mpol-\u003emode.\\n\\n[  151.412631] BUG: KASAN: slab-use-after-free in __futex_key_to_node (kernel/futex/core.c:349)\\n[  151.414046] Read of size 2 at addr ffff888001c49634 by task e/87\\n\\n[  151.415969] Call Trace:\\n\\n[  151.416732]  __asan_load2 (mm/kasan/generic.c:271)\\n[  151.416777]  __futex_key_to_node (kernel/futex/core.c:349)\\n[  151.416822]  get_futex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593)\\n\\nFix by adding rcu to __mpol_put().\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/190a8c48ff623c3d67cb295b4536a660db2012aa\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7e196194ea27bd49adf3551e2aceb83498eb73fe\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/853f70c67d1b37e368fdcb3e328c4b8c04f53ac0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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