CVE-2026-97417 (GCVE-0-2026-97417)

Vulnerability from cvelistv5 – Published: 2026-09-24 16:03 – Updated: 2026-09-25 12:43
VLAI
Title
netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9 , < 7ecfa46a536578a7ed335ddf31a854127268c27c (git)
Affected: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9 , < 4abc1af7ac209c066f4e5dd75cdd56876e5829a9 (git)
Affected: bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9 , < d3bf9eae486490832bd08fd62ab0ac601f346bd4 (git)
guessed Create a notification for this product.
Linux Linux Affected: 3.1
Unaffected: 0 , < 3.1 (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "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": "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": "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": "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": "2026-09-25T12:43:52.382Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "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": "2026-09-25T12:43:52.382Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-97417",
      "date": "2026-09-25",
      "epss": "0.00426",
      "percentile": "0.34245"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "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": "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": "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"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "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."
          }
        ],
        "id": "CVE-2026-97417",
        "lastModified": "2026-09-25T13:17:25.243",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 3.6,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-24T17:17:19.457",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/4abc1af7ac209c066f4e5dd75cdd56876e5829a9"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/7ecfa46a536578a7ed335ddf31a854127268c27c"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/d3bf9eae486490832bd08fd62ab0ac601f346bd4"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-09-25T09:37:03+00:00",
      "cve": "CVE-2026-97417",
      "id": "CVE-2026-97417",
      "initial_release_date": "2026-09-24T00:00:00+00:00",
      "product_status:known_affected": "276",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97417.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-09-24T23:46:34Z",
      "cve": "CVE-2026-97417",
      "id": "CVE-2026-97417",
      "initial_release_date": "2026-09-24T23:46:34Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-97417",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-97417.json",
      "version": "2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.