CVE-2026-98033 (GCVE-0-2026-98033)
Vulnerability from cvelistv5
Published
2026-09-25 10:23
Modified
2026-10-21 12:54
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Preserve inner map identity in callback frames Callback frame constructors initialize map-typed argument registers with __mark_reg_known_zero() and then restore map_ptr. This clears map_uid, which is the only field distinguishing inner maps that share an inner_map_meta template. When a timer callback invokes bpf_for_each_map_elem() on a second inner map, both the saved first map and the second map value can reach the nested callback as the same template with map_uid zero. bpf_timer_init() then accepts pairing the timer from the second map with the first map. The runtime records the first map in the timer without taking a reference. Freeing that map does not find the timer stored in the second map, so a later timer callback dereferences the freed map. Copy map_uid from the same caller register as map_ptr when constructing for-each, timer/workqueue, and task-work callback arguments. The existing identity check can then reject mismatched inner maps while allowing a callback value to be paired with its actual map.
References
Impacted products
Vendor Product Version
Linux Linux Version: 69c087ba6225b574afb6e505b72cb75242a3d844
Version: 69c087ba6225b574afb6e505b72cb75242a3d844
Version: 69c087ba6225b574afb6e505b72cb75242a3d844
Version: 69c087ba6225b574afb6e505b72cb75242a3d844
Version: 69c087ba6225b574afb6e505b72cb75242a3d844
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
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          "programFiles": [
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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": "5.13"
            },
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              "version": "0",
              "versionType": "semver"
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              "version": "6.6.160",
              "versionType": "semver"
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              "version": "6.12.114",
              "versionType": "semver"
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
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              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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\nbpf: Preserve inner map identity in callback frames\n\nCallback frame constructors initialize map-typed argument registers with\n__mark_reg_known_zero() and then restore map_ptr. This clears map_uid,\nwhich is the only field distinguishing inner maps that share an\ninner_map_meta template.\n\nWhen a timer callback invokes bpf_for_each_map_elem() on a second inner\nmap, both the saved first map and the second map value can reach the nested\ncallback as the same template with map_uid zero. bpf_timer_init() then\naccepts pairing the timer from the second map with the first map.\n\nThe runtime records the first map in the timer without taking a reference.\nFreeing that map does not find the timer stored in the second map, so a\nlater timer callback dereferences the freed map.\n\nCopy map_uid from the same caller register as map_ptr when constructing\nfor-each, timer/workqueue, and task-work callback arguments. The existing\nidentity check can then reject mismatched inner maps while allowing a\ncallback value to be paired with its actual map."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:54:07.398Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/cf85e4f94d7feef8b3c4c90dbe2468595a48393b"
        },
        {
          "url": "https://git.kernel.org/stable/c/166221c52d3ca332f8699a854efca8e2704bb137"
        },
        {
          "url": "https://git.kernel.org/stable/c/08b534bafdd9de65b6374474a8fe719c90eb3b01"
        },
        {
          "url": "https://git.kernel.org/stable/c/66ff2eff093d2a0838f39c713eeb590bc0946c2a"
        },
        {
          "url": "https://git.kernel.org/stable/c/b90c5d770dad910fb89e6c1b15052a8a1e8db752"
        }
      ],
      "title": "bpf: Preserve inner map identity in callback frames",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98033",
    "datePublished": "2026-09-25T10:23:48.761Z",
    "dateReserved": "2026-09-25T10:19:56.070Z",
    "dateUpdated": "2026-10-21T12:54:07.398Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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