CVE-2026-97417 (GCVE-0-2026-97417)
Vulnerability from cvelistv5
Published
2026-09-24 16:03
Modified
2026-10-03 10:58
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack() The timestamp-only fast path dereferences the option stream as *(__be32 *)ptr, which assumes 4-byte alignment that the TCP option stream does not guarantee. Use get_unaligned_be32() instead, which reads the value safely and already returns host byte order, so the htonl() on the comparison constant can be dropped. This matches the existing get_unaligned_be32() use later in the same function.
Impacted products
Vendor Product Version
Linux Linux Version: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9
Version: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9
Version: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9
Version: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9
Version: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9
Version: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9
Version: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_conntrack_proto_tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "740ad3d17a281f7764dda4dbeb37cea52e2e31ae",
              "status": "affected",
              "version": "bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9",
              "versionType": "git"
            },
            {
              "lessThan": "a0523267de2523522b0f70972dd1ffa22ec6176c",
              "status": "affected",
              "version": "bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9",
              "versionType": "git"
            },
            {
              "lessThan": "55bcc3376cd7b18954cc9814da697504fdaf12bf",
              "status": "affected",
              "version": "bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9",
              "versionType": "git"
            },
            {
              "lessThan": "0d5ad732e4fdc569eb85861115e8f7b4c2c67852",
              "status": "affected",
              "version": "bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9",
              "versionType": "git"
            },
            {
              "lessThan": "7ecfa46a536578a7ed335ddf31a854127268c27c",
              "status": "affected",
              "version": "bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9",
              "versionType": "git"
            },
            {
              "lessThan": "4abc1af7ac209c066f4e5dd75cdd56876e5829a9",
              "status": "affected",
              "version": "bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9",
              "versionType": "git"
            },
            {
              "lessThan": "d3bf9eae486490832bd08fd62ab0ac601f346bd4",
              "status": "affected",
              "version": "bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_conntrack_proto_tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.1"
            },
            {
              "lessThan": "3.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.271",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.222",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.189",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()\n\nThe timestamp-only fast path dereferences the option stream as\n*(__be32 *)ptr, which assumes 4-byte alignment that the TCP option\nstream does not guarantee. Use get_unaligned_be32() instead, which\nreads the value safely and already returns host byte order, so the\nhtonl() on the comparison constant can be dropped.\n\nThis matches the existing get_unaligned_be32() use later in the same\nfunction."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - ipv4_conntrack_in() on NF_INET_PRE_ROUTING calls nf_conntrack_in()\u2192nf_conntrack_tcp_packet()\u2192tcp_in_window()\u2192tcp_sack(); the *(__be32 *)ptr load reads the first four option bytes of a received TCP segment (doff=8, 12-byte NOP-NOP-TIMESTAMP block) that the remote peer put on the wire.\nAC:L - Default tcp_loose=1 makes tcp_new() set IP_CT_TCP_FLAG_SACK_PERM on both directions for a non-SYN ACK, so one attacker TCP ACK with doff=8 (length==TCPOLEN_TSTAMP_ALIGNED) reaches tcp_sack()\u0027s timestamp fast path; on strict-alignment NAT/PPPoE paths where those options are 2-mod-4, *(__be32 *)ptr faults with no race.\nPR:N - ipv4_conntrack_in()/ipv6_conntrack_in() run in NF_INET_PRE_ROUTING; tcp_error() only checks header length, flags, and checksum before nf_conntrack_tcp_packet() reaches tcp_sack(), with no socket, credentials, or TCP-handshake authentication.\nUI:N - The PRE_ROUTING conntrack hook invokes tcp_sack() from softirq on the attacker\u0027s own TCP segment; no victim must mount media, open a file, or take any other interactive action.\nS:U - An alignment fault in tcp_sack() oopses the same host kernel that is conntracking the TCP flow; it does not cross a VM, guest-to-host, IOMMU, or other security authority.\nC:N - The timestamp fast path loads four in-bounds bytes of the packet\u0027s own TCP option stream after skb_header_pointer(..., length==12, ...); it is not an OOB or UAF read, and a strict-alignment fault discloses nothing beyond those attacker-supplied bytes.\nI:N - tcp_sack()\u0027s defect is a read-only *(__be32 *)ptr of the option bytes; it does not write conntrack state or adjacent objects, and the fix only replaces that load with get_unaligned_be32().\nA:H - On SPARC, MIPS, and pre-v6 ARM (typical OpenWrt/CPE NAT boxes), the misaligned __be32 load in tcp_sack() raises a kernel alignment exception/oops/panic in netfilter softirq, fully denying host availability and repeatable by resending the segment."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-03T10:58:08.961Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/740ad3d17a281f7764dda4dbeb37cea52e2e31ae"
        },
        {
          "url": "https://git.kernel.org/stable/c/a0523267de2523522b0f70972dd1ffa22ec6176c"
        },
        {
          "url": "https://git.kernel.org/stable/c/55bcc3376cd7b18954cc9814da697504fdaf12bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/0d5ad732e4fdc569eb85861115e8f7b4c2c67852"
        },
        {
          "url": "https://git.kernel.org/stable/c/7ecfa46a536578a7ed335ddf31a854127268c27c"
        },
        {
          "url": "https://git.kernel.org/stable/c/4abc1af7ac209c066f4e5dd75cdd56876e5829a9"
        },
        {
          "url": "https://git.kernel.org/stable/c/d3bf9eae486490832bd08fd62ab0ac601f346bd4"
        }
      ],
      "title": "netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97417",
    "datePublished": "2026-09-24T16:03:27.069Z",
    "dateReserved": "2026-09-24T14:53:16.867Z",
    "dateUpdated": "2026-10-03T10:58:08.961Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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