FKIE_CVE-2026-98033

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 11:17
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
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/66ff2eff093d2a0838f39c713eeb590bc0946c2a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b90c5d770dad910fb89e6c1b15052a8a1e8db752
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "66ff2eff093d2a0838f39c713eeb590bc0946c2a",
              "status": "affected",
              "version": "69c087ba6225b574afb6e505b72cb75242a3d844",
              "versionType": "git"
            },
            {
              "lessThan": "b90c5d770dad910fb89e6c1b15052a8a1e8db752",
              "status": "affected",
              "version": "69c087ba6225b574afb6e505b72cb75242a3d844",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-98033",
  "lastModified": "2026-09-25T11:17:32.003",
  "metrics": {},
  "published": "2026-09-25T11:17:32.003",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/66ff2eff093d2a0838f39c713eeb590bc0946c2a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b90c5d770dad910fb89e6c1b15052a8a1e8db752"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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