CVE-2026-63924 (GCVE-0-2026-63924)
Vulnerability from cvelistv5
Published
2026-07-19 14:55
Modified
2026-08-05 12:37
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo() ipv6_hop_jumbo() calls pskb_trim_rcsum(), which can change skb pointers. Let's recompute nh pointer to make sure any change won't mess things up.
References
Impacted products
Vendor Product Version
Linux Linux Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/exthdrs.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "version": "0",
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              "status": "unaffected",
              "version": "6.6.143",
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              "status": "unaffected",
              "version": "6.12.93",
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              "status": "unaffected",
              "version": "6.18.35",
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              "version": "7.0.12",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "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\nipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()\n\nipv6_hop_jumbo() calls pskb_trim_rcsum(), which can change skb pointers.\nLet\u0027s recompute nh pointer to make sure any change won\u0027t mess things up."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is in the IPv6 input path (ipv6_rcv \u2192 ip6_rcv_core \u2192 ipv6_parse_hopopts) triggered by a crafted IPv6 packet with hop-by-hop options containing a Jumbo Payload TLV, reachable from any remote peer that can deliver IPv6 to the host.\nAC:L - An attacker fully controls the crafted IPv6 packet (HBH layout, jumbo length, trailing TLVs) and can send it repeatedly; once the skb is cloned/shared during receive and pskb_trim_rcsum reallocates the head, the stale-pointer UAF is deterministically triggered without races or victim-specific state.\nPR:N - No authentication or local privileges are required; any unauthenticated remote host that can send IPv6 traffic to a listening interface reaches the vulnerable receive handler with no capability or namespace checks along the path.\nUI:N - Exploitation requires only delivery of a malicious IPv6 packet and does not depend on any victim user action such as opening files, clicking links, or mounting filesystems.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel security domain; it does not cross a VM, container, or IOMMU boundary by itself.\nC:H - Continued HBH TLV parsing through the stale nh pointer is a use-after-free read of freed skb head memory, which per kernel guidance enables arbitrary kernel memory disclosure when the freed slab is reused.\nI:H - Stale-pointer UAF during TLV length/type parsing can yield unbounded out-of-bounds reads and corrupt subsequent parsing state, providing memory corruption primitives that can be developed into arbitrary kernel writes or code execution.\nA:H - Dereferencing the freed network-header pointer during TLV parsing can cause immediate kernel oops/panic from invalid memory access, and UAF-triggered parsing errors reliably drop or crash the receive path."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:37:19.118Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b3ac54e5c905f86d22b502eacb5686a282c5659f"
        },
        {
          "url": "https://git.kernel.org/stable/c/645b99b1a185c91a79bdac4c5de0f91b212d64f0"
        },
        {
          "url": "https://git.kernel.org/stable/c/9e883eaa878f4337b5873c706efb5a192364ed18"
        },
        {
          "url": "https://git.kernel.org/stable/c/bddaa4dfc7f36e1ee343a0622f69288af2b9ace9"
        },
        {
          "url": "https://git.kernel.org/stable/c/72af7beae774e46ed543f3f2f267bf0a141bfcdd"
        },
        {
          "url": "https://git.kernel.org/stable/c/c512e1c819dfbf6ae95ee7a44b65b9ad98979157"
        },
        {
          "url": "https://git.kernel.org/stable/c/2b56bbd928c030894c270cd33d60286326919458"
        },
        {
          "url": "https://git.kernel.org/stable/c/d47548a36639095939f4747d4c43f2271366f565"
        }
      ],
      "title": "ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()",
      "x_generator": {
        "engine": "bippy-1.2.0"
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63924",
    "datePublished": "2026-07-19T14:55:25.702Z",
    "dateReserved": "2026-07-19T07:54:57.021Z",
    "dateUpdated": "2026-08-05T12:37:19.118Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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