CVE-2026-64226 (GCVE-0-2026-64226)
Vulnerability from cvelistv5
Published
2026-07-24 15:23
Modified
2026-08-05 12:40
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Avoid UAF in scx_root_enable_workfn() init failure path In scx_root_enable_workfn(), put_task_struct(p) is called before scx_error() dereferences p->comm and p->pid. If the iterator's reference is the last drop, the task is freed synchronously and the deref becomes a UAF. Move put_task_struct() past scx_error().
References
Impacted products
Vendor Product Version
Linux Linux Version: f0e1a0643a59bf1f922fa209cec86a170b784f3f
Version: f0e1a0643a59bf1f922fa209cec86a170b784f3f
Version: f0e1a0643a59bf1f922fa209cec86a170b784f3f
Version: f0e1a0643a59bf1f922fa209cec86a170b784f3f
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "cf396941901858b0de426cdcd3974eea6a02c98c",
              "status": "affected",
              "version": "f0e1a0643a59bf1f922fa209cec86a170b784f3f",
              "versionType": "git"
            },
            {
              "lessThan": "45c7c4e3db8b700307313c035ea08be829a7f21b",
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              "versionType": "git"
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              "status": "affected",
              "version": "f0e1a0643a59bf1f922fa209cec86a170b784f3f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.92",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Avoid UAF in scx_root_enable_workfn() init failure path\n\nIn scx_root_enable_workfn(), put_task_struct(p) is called before scx_error()\ndereferences p-\u003ecomm and p-\u003epid. If the iterator\u0027s reference is the last\ndrop, the task is freed synchronously and the deref becomes a UAF.\n\nMove put_task_struct() past scx_error()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable enable path is reached locally through bpf() struct_ops map preparation and BPF_LINK_CREATE, which invokes scx_enable() and scx_root_enable_workfn().\nAC:L - The attacker can make ops.init_task() return an error for a selected task while concurrently causing that task to exit, controlling both sides of the race and allowing repeated attempts.\nPR:L - Although ordinary attachment requires init-namespace CAP_BPF and CAP_PERFMON, BPF tokens can delegate the necessary struct_ops permissions to a non-init user namespace. Under the highest defensible deployment scenario, this is reachable by a locally authorized but non-administrative user.\nUI:N - The attacker can attach the scheduler and coordinate the target task\u0027s exit without requiring another user to take any action.\nS:U - The vulnerable sched_ext code and the affected kernel memory and execution context belong to the same kernel security authority.\nC:H - The freed task_struct is dereferenced through p-\u003ecomm as a string and p-\u003epid, potentially exposing reclaimed or adjacent slab contents through the sched_ext diagnostic buffer. Consistent with the required UAF guidance, confidentiality impact is High.\nI:H - The access occurs after a task_struct slab object has been freed and can be influenced through heap reuse and spraying. Applying the required higher-severity treatment for UAF conditions, potential memory-corruption and control-flow impact warrants High.\nA:H - The stale string dereference can cause a KASAN failure, invalid-memory access, kernel oops, or panic, and the attacker can repeat the controlled failure-and-exit sequence."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:40:11.672Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/cf396941901858b0de426cdcd3974eea6a02c98c"
        },
        {
          "url": "https://git.kernel.org/stable/c/45c7c4e3db8b700307313c035ea08be829a7f21b"
        },
        {
          "url": "https://git.kernel.org/stable/c/57e19ba3f58a67eb924022a5a60b67fd08e5cbbd"
        },
        {
          "url": "https://git.kernel.org/stable/c/9a415cc53711f2238e0f0ca8a6bcc796c003b127"
        }
      ],
      "title": "sched_ext: Avoid UAF in scx_root_enable_workfn() init failure path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64226",
    "datePublished": "2026-07-24T15:23:10.388Z",
    "dateReserved": "2026-07-19T15:36:31.771Z",
    "dateUpdated": "2026-08-05T12:40:11.672Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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