CVE-2026-97905 (GCVE-0-2026-97905)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:22 – Updated: 2026-09-25 10:22
VLAI
Title
cpufreq: zero-initialize policy cpumask before sysfs publication
Summary
In the Linux kernel, the following vulnerability has been resolved: cpufreq: zero-initialize policy cpumask before sysfs publication cpufreq_policy_alloc() allocates policy->cpus with alloc_cpumask_var(), i.e. without __GFP_ZERO, unlike the sibling related_cpus and real_cpus masks. With CONFIG_CPUMASK_OFFSTACK=y the mask is a separate kmalloc_node() allocation, so its bitmap holds whatever the slab allocator left behind: cpufreq_online() cpufreq_policy_alloc() alloc_cpumask_var(&policy->cpus) /* bitmap is uninitialized */ kobject_init_and_add() /* policy%u/ appears in sysfs */ cpufreq_policy_online() cpumask_copy(policy->cpus, cpumask_of(cpu)) /* first valid value */ This leaves a window in which the sysfs attributes are already reachable while policy->cpus is still garbage. show()/store() gate on policy_is_inactive(), i.e. cpumask_empty(policy->cpus), so a non-zero bitmap makes them run the attribute callbacks on a policy that is not initialized yet. Fix this by using zalloc_cpumask_var() for policy->cpus.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2fc3384dc75bf7333384c7a16d12c796f61c3f56 , < 0de2f3918fbbbb767e7e716178194b66560dd12a (git)
Affected: 2fc3384dc75bf7333384c7a16d12c796f61c3f56 , < 6e166b9281dec98aed19213a84235250e5fdb081 (git)
Affected: 2fc3384dc75bf7333384c7a16d12c796f61c3f56 , < bbc0472d2270bf732142ca71579d6ede636174ed (git)
Affected: 2fc3384dc75bf7333384c7a16d12c796f61c3f56 , < 54d37bcf2f497140b9207968557ddb484058e749 (git)
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Linux Linux Affected: 4.2
Unaffected: 0 , < 4.2 (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
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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\ncpufreq: zero-initialize policy cpumask before sysfs publication\n\ncpufreq_policy_alloc() allocates policy-\u003ecpus with alloc_cpumask_var(),\ni.e. without __GFP_ZERO, unlike the sibling related_cpus and real_cpus\nmasks. With CONFIG_CPUMASK_OFFSTACK=y the mask is a separate\nkmalloc_node() allocation, so its bitmap holds whatever the slab allocator\nleft behind:\n\n  cpufreq_online()\n    cpufreq_policy_alloc()\n      alloc_cpumask_var(\u0026policy-\u003ecpus)    /* bitmap is uninitialized */\n      kobject_init_and_add()              /* policy%u/ appears in sysfs */\n    cpufreq_policy_online()\n      cpumask_copy(policy-\u003ecpus, cpumask_of(cpu))  /* first valid value */\n\nThis leaves a window in which the sysfs attributes are already reachable\nwhile policy-\u003ecpus is still garbage. show()/store() gate on\npolicy_is_inactive(), i.e. cpumask_empty(policy-\u003ecpus), so a non-zero\nbitmap makes them run the attribute callbacks on a policy that is not\ninitialized yet.\n\nFix this by using zalloc_cpumask_var() for policy-\u003ecpus."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T10:22:31.046Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/0de2f3918fbbbb767e7e716178194b66560dd12a"
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    "cveId": "CVE-2026-97905",
    "datePublished": "2026-09-25T10:22:31.046Z",
    "dateReserved": "2026-09-25T10:18:58.200Z",
    "dateUpdated": "2026-09-25T10:22:31.046Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-28",
      "epss": "0.002",
      "percentile": "0.08797"
    },
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      "cve": "CVE-2026-97905",
      "id": "msrc_CVE-2026-97905",
      "initial_release_date": "2026-09-28T00:33:44.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "cpufreq: zero-initialize policy cpumask before sysfs publication",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-97905.json",
      "version": "1"
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncpufreq: zero-initialize policy cpumask before sysfs publication\n\ncpufreq_policy_alloc() allocates policy-\u003ecpus with alloc_cpumask_var(),\ni.e. without __GFP_ZERO, unlike the sibling related_cpus and real_cpus\nmasks. With CONFIG_CPUMASK_OFFSTACK=y the mask is a separate\nkmalloc_node() allocation, so its bitmap holds whatever the slab allocator\nleft behind:\n\n  cpufreq_online()\n    cpufreq_policy_alloc()\n      alloc_cpumask_var(\u0026policy-\u003ecpus)    /* bitmap is uninitialized */\n      kobject_init_and_add()              /* policy%u/ appears in sysfs */\n    cpufreq_policy_online()\n      cpumask_copy(policy-\u003ecpus, cpumask_of(cpu))  /* first valid value */\n\nThis leaves a window in which the sysfs attributes are already reachable\nwhile policy-\u003ecpus is still garbage. show()/store() gate on\npolicy_is_inactive(), i.e. cpumask_empty(policy-\u003ecpus), so a non-zero\nbitmap makes them run the attribute callbacks on a policy that is not\ninitialized yet.\n\nFix this by using zalloc_cpumask_var() for policy-\u003ecpus."
          }
        ],
        "id": "CVE-2026-97905",
        "lastModified": "2026-09-25T11:17:17.403",
        "metrics": {},
        "published": "2026-09-25T11:17:17.403",
        "references": [
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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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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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.