CVE-2026-63922 (GCVE-0-2026-63922)
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 after handling HAO option ip6_parse_tlv() caches skb_network_header(skb) in nh while walking IPv6 TLVs. ipv6_dest_hao() may call pskb_expand_head() for a cloned skb, which can move the skb head and invalidate the cached network header pointer. Refresh nh after ipv6_dest_hao() returns so any trailing padding or TLVs are parsed from the current skb head. This matches the existing pattern used in ip6_parse_tlv() after helpers that can modify skb header storage.
References
Impacted products
Vendor Product Version
Linux Linux Version: a831f5bbc89a9978795504be9e1ff412043f8f77
Version: a831f5bbc89a9978795504be9e1ff412043f8f77
Version: a831f5bbc89a9978795504be9e1ff412043f8f77
Version: a831f5bbc89a9978795504be9e1ff412043f8f77
Version: a831f5bbc89a9978795504be9e1ff412043f8f77
Version: a831f5bbc89a9978795504be9e1ff412043f8f77
Version: a831f5bbc89a9978795504be9e1ff412043f8f77
Version: a831f5bbc89a9978795504be9e1ff412043f8f77
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/exthdrs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "2.6.19"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
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            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
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            },
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              "status": "unaffected",
              "version": "7.0.12",
              "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": "5.10.259",
                  "versionStartIncluding": "2.6.19",
                  "vulnerable": true
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
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                  "vulnerable": true
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                {
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: exthdrs: refresh nh after handling HAO option\n\nip6_parse_tlv() caches skb_network_header(skb) in nh while walking\nIPv6 TLVs.\n\nipv6_dest_hao() may call pskb_expand_head() for a cloned skb, which can\nmove the skb head and invalidate the cached network header pointer.\nRefresh nh after ipv6_dest_hao() returns so any trailing padding or TLVs\nare parsed from the current skb head.\n\nThis matches the existing pattern used in ip6_parse_tlv() after helpers\nthat can modify skb header storage."
        }
      ],
      "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 reached on the standard IPv6 input path (ipv6_rcv \u2192 ip6_input \u2192 ip6_protocol_deliver_rcu \u2192 ipv6_destopt_rcv) when a remotely sent IPv6 packet carries a Destination Options header processed by ip6_parse_tlv().\nAC:L - The attacker fully controls the crafted IPv6 Destination Options layout (HAO TLV followed by trailing TLVs/padding); once CONFIG_IPV6_MIP6 and matching XFRM state exist on the target, triggering the stale-pointer condition is a reliable single-packet attack without races or victim-specific timing.\nPR:N - No local privileges or authentication are required; any remote host that can deliver IPv6 traffic to a listening interface can reach this pre-authentication receive-path parser (destopt_protocol uses INET6_PROTO_NOPOLICY).\nUI:N - Exploitation requires only sending a malicious IPv6 packet; no victim interaction such as opening files, clicking links, or mounting filesystems is needed.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the kernel\u2019s security authority; it does not cross VM, container, or IOMMU boundaries.\nC:H - After pskb_expand_head() frees the old skb head, ip6_parse_tlv() continues parsing trailing TLVs through the stale nh pointer, causing out-of-bounds/use-after-free reads of kernel heap memory that can disclose sensitive kernel data.\nI:H - Use-after-free of the skb head buffer during TLV parsing is heap memory corruption that can be leveraged for arbitrary kernel writes and control-flow hijacking, not merely a bounded parse error.\nA:H - Reading through the stale network-header pointer into freed or invalid memory can cause kernel oops/panic or unrecoverable instability, satisfying high availability impact even before full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:37:16.967Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b3ac54e5c905f86d22b502eacb5686a282c5659f"
        },
        {
          "url": "https://git.kernel.org/stable/c/f8aabed3ff3e986920cf02a2a2785e08e586b234"
        },
        {
          "url": "https://git.kernel.org/stable/c/1a11eb7431e3d2882f5bd5939c5a9bbc65ccf4d1"
        },
        {
          "url": "https://git.kernel.org/stable/c/12d957979e4a800167842f1b42be6a606d227ebe"
        },
        {
          "url": "https://git.kernel.org/stable/c/ff375ed1cba81392346c5bfbf0bb7a13b2946f99"
        },
        {
          "url": "https://git.kernel.org/stable/c/751db1b802a067b7fff25880f4e9f9152a171538"
        },
        {
          "url": "https://git.kernel.org/stable/c/9b6dcc0a39fd71752937f0b6b3973e1416085dcf"
        },
        {
          "url": "https://git.kernel.org/stable/c/f7b52afe3592eae66e160586b45a3f2242972c63"
        }
      ],
      "title": "ipv6: exthdrs: refresh nh after handling HAO option",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63922",
    "datePublished": "2026-07-19T14:55:24.268Z",
    "dateReserved": "2026-07-19T07:54:57.021Z",
    "dateUpdated": "2026-08-05T12:37:16.967Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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