CVE-2026-98591 (GCVE-0-2026-98591)
Vulnerability from cvelistv5
Published
2026-10-18 15:19
Modified
2026-10-19 09:22
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix bounds check for skb-backed dynptrs The skb_pointer_if_linear() function checks whether a memory region of length len starting at offset off into the skb is in the linear area, and returns a pointer to the region if so. The check currently subtracts between skb_headlen and offset of the check, and since skb_headlen is unsigned the subtraction can underflow. This causes the bounds check to spuriously pass and generate an arbitrary pointer of the form *(skb->data + off). The only user of this helper is currently skb-backed BPF dynptr code. Returning the wrong pointer leads to the dynptr erroneously being backed with invalid memory. Ensure the subtraction cannot underflow, and fail the check if it would. Use u64 arithmetic to also prevent overflow when calculating (skb_headlen(skb) - off) since off is unsigned.
References
Impacted products
Vendor Product Version
Linux Linux Version: 6f5a630d7c57cd79b1f526a95e757311e32d41e5
Version: 6f5a630d7c57cd79b1f526a95e757311e32d41e5
Version: 6f5a630d7c57cd79b1f526a95e757311e32d41e5
Version: 6f5a630d7c57cd79b1f526a95e757311e32d41e5
Version: 6f5a630d7c57cd79b1f526a95e757311e32d41e5
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/skbuff.h"
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              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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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: Fix bounds check for skb-backed dynptrs\n\nThe skb_pointer_if_linear() function checks whether a\nmemory region of length len starting at offset off into\nthe skb is in the linear area, and returns a pointer to\nthe region if so. The check currently subtracts between\nskb_headlen and offset of the check, and since skb_headlen\nis unsigned the subtraction can underflow. This causes the\nbounds check to spuriously pass and generate an arbitrary\npointer of the form *(skb-\u003edata + off).\n\nThe only user of this helper is currently skb-backed BPF\ndynptr code. Returning the wrong pointer leads to the\ndynptr erroneously being backed with invalid memory.\n\nEnsure the subtraction cannot underflow, and fail the check if\nit would. Use u64 arithmetic to also prevent overflow when\ncalculating (skb_headlen(skb) - off) since off is unsigned."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:22:16.758Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1b923538598be768e9f2f258a77a083d00e0c78b"
        },
        {
          "url": "https://git.kernel.org/stable/c/37877a24758068742fef687a7cf5362360dde1d1"
        },
        {
          "url": "https://git.kernel.org/stable/c/1196903a27cac5c929c7517e987a8d159f20c5e5"
        },
        {
          "url": "https://git.kernel.org/stable/c/39ffceaddb10753eac12785dba6ac0673860b4ac"
        },
        {
          "url": "https://git.kernel.org/stable/c/ed6eec97b534979dcf28b40c389cee57bd6561d4"
        }
      ],
      "title": "bpf: Fix bounds check for skb-backed dynptrs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98591",
    "datePublished": "2026-10-18T15:19:03.567Z",
    "dateReserved": "2026-09-25T10:25:14.359Z",
    "dateUpdated": "2026-10-19T09:22:16.758Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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